Atomic 4
Frequently Asked Questions (FAQ)

Written by Robert Hess
Atomic Four Engine Service
Vancouver, Canada

How do I align my engine?

Universal inboard marine engines should be installed so that the engine mounts are securely attached using the correct fasteners, aligned with the propeller shaft to a tolerance of .05 mm (.002 in) measured at the engine and propeller shaft flange face, with the propeller shaft aligned and centred with the propeller shaft strut cutlass bearing and stern tube. During adjustment any flexible (ie rubber) engine mounts should be extended using pry bars or wedges to bring the engine into the same position it will be when the boat is under power at the speed at which it will usually be run (ie normal cruising speed). To determine engine mount deflection position under power, measure the position of the engine close to each mount with the engine stopped, and then measure it again under power (you can do this tied to the dock) using a dial gauge or fixed pointer. Excessive deflection of the engine under power may mean the engine mounts are loose or the flexible engine mount material is worn out.

When aligning the engine, adjust the alignment with the 2 rear engine mounts and 1 forward mount (for V drive engines adjust 1 rear engine mount and 2 forward mounts), leaving the 4th mount loose until the alignment is correct. Take up the clearance on the 4th mount with the lower adjusting nut or shims. Then tighten all 4 mount top nuts. This will prevent the engine block/pan from being twisted (and possibly cracked) during final tightening of the mount nuts. If the alignment changes when the top nuts are tightened, the 4th mount clearance was adjusted either too much or not enough. Engine mount deflection and engine alignment should be checked once per year, as well as whenever the boat has been lifted from the water, and mounts replaced or tightened and alignment adjusted as required.


What size propeller should I use?

The boat must be fitted with a properly balanced propeller of a pitch and diameter that will allow the engine to reach specified full rpm during full throttle, top speed testing as per the engine specifications (diesel engine specifications usually state the engine must be able to reach very close to maximum governor engine speed, direct drive Atomic Four engines must be able to reach a minimum of 1,800 rpm, and Atomic Four engines fitted with a reduction gear set in a reduction gearbox or V-drive should reach over 3,000 rpm). If the engine cannot reach minimum rated rpm the propeller is too large and must be replaced with one with a smaller pitch and/or diameter. The use of a propeller that restricts engine rpm to below specification will create a lugging condition that will cause engine overheating and damage. 3 blade propellers (we like the Campbell Sailor 3 blade propeller) are usually recommended for cruising boats in areas with strong currents and tides. 2 blade propellers are useful because they can be "parked" in a vertical position which will allow the upper blade to be shielded by the shaft strut, allowing slightly more speed under sail. Folding and feathering propellers are usually fitted to boats used for racing, however when fitting them type keep in mind that it is quite common for engines to be damaged when an excessively large used folding/feathering propeller from a larger boat is installed for racing.


Should I install a water separator fuel filter assembly?

Many marine engine problems are caused by water condensation in fuel tanks, and water / dirt transferred from marine fuel depot (ie marina) tanks. Clean fuel is just as important to gasoline engines as it is to diesel engines, and a water separator filter/fuel filter should be used for both types of engine. Gasoline engine water separator filters should not be fitted with a glass sediment bowl or bowl drain petcock. Fuel filter elements should be changed at least annually, preferably in the autumn. We recommend the Racor 320R-RAC-02 filter assembly for gasoline engines, and the Racor 500MA-P-10 filter assembly for diesel engines. Most diesel engines will also have an engine mounted secondary 2 micron or 10 micron filter. The "P" in the 500MA model number specifies Filter Bowl Water Probe Assembly #RK21069, which works in conjunction with Water Detection Warning Module #RK12870 (a dash mounted warning light and buzzer which must be purchased separately) to reduce the need to drain water from the filter bowl every day when the boat is being used. We suggest the 500MA be fitted with Bowl Drain Valve Petcock #RK19492 to facilitate bowl draining when it is necessary.


What oil should I use?

We recommend gas and diesel Universal marine engines operating in southern Canada / northern US with ambient temperatures over 10 C / 50 F, including Atomic Four engines, use SAE 10 - 40 multi-grade oil. Gasoline engine oil should have an API rating of "SJ" (the European equivalent for an "SJ" rating is an ACEA rating of "A3-96"). Diesel engine oil should have an API rating of "CH-4" (the European equivalent for a "CH-4" rating is an ACEA rating of "E2-96"). SAE 15 - 40 "fleet oil" with combined SJ and CH-4 ratings is also acceptable for both gas and diesel Universal engines.

We recommend the use of a top quality brand-name oil such as Petro-Canada, Valvoline, or Shell. Do not mix brands.


Should I add supplements to my oil?

No. Modern engine oil already has lots of additives, including detergents, dispersants, corrosion inhibitors, antioxidants, viscosity-index improvers, extreme-pressure additives, and 28 other chemicals. Do not add any oil supplements (ie Slick 50, STP, Marvel Mystery Oil, kerosene, diesel fuel, etc) to the oil. Oil supplements can damage the engine, and can also cause integral clutch-type transmissions such as the Paragon transmission used in the Atomic Four to slip under full load. If you feel the need to add Marvel Mystery Oil or a similar product to the oil to free up suspected stuck rings or valves, try using 5-30 oil and changing it several times after approximately 10 hours of running. You can also buy a can of Engine Flush at an auto parts store and add it to the oil to flush the engine just before changing the oil. Stuck valves are usually caused by cold running, so before assuming valve problems are oil related, make sure the thermostat is bringing the engine up to the correct temperature: 140 F for raw water cooled engines running in salt water, and 180 F for engines equipped with heat exchangers.


Should I add supplements to my fuel?

No. Modern engine fuel already has lots of additives: N-hexyl and octyl nitrate in diesel fuel, and anti-knock agents, scavengers, phosphorous additives, antioxidants, metal deactivators, surface-active agents, deposit control additives, deicing agents, dyes, octane boosters plus 43 other additives in gasoline. Adding any type of oil to the fuel dumps unnecessary oil in the water with the exhaust in the same way a 2 stroke outboard does. The Champion spark plug company "Spark Plug Handbook" warns "Champion does not recommend the use of fuel additives which leave deposits on the core nose of the spark plug". Under the heading "Splash Deposits" the Champion handbook states "the use of fuel additives, carburetor, and choke cleaners or other agressive solvents before installing new plugs is the most common cause of this condition [splash deposits]", and under the heading "Fuel Additives" it states "red to purple deposits on one side of the core nose are an indication of fuel additive. While many of these deposits are non-conductive and do not contribute to lack of performance, some fuel additives contain octane boosters that leave conductive deposits on the core nose". Do not add anything to your fuel tank except when you're putting the boat in winter storage, when you may want to add a small amount of gas line antifreeze to gasoline and diesel fuel conditioner to diesel fuel.


Atomic Four engines fitted with direct drive marine gears use a ball bearing with a "Z" designation for the rear thrust bearing. Can I use a regular ball bearing without the shield?

The Z designation in the bearing model number means the bearing has a shield on one side of the race. Shields are non-contact metal or plastic covers which allow for high speed operation by restricting (not stopping) the oil spray in the gearbox from flooding the bearing, so the bearing should be installed with the shield facing the front of the engine. The shield also restricts (not stops) oil flow to the rear flange oil seal at the rear of the bearing. Fitting a bearing without a shield allows the full volume of oil spray to reach the bearing and seal, which can cause the bearing to receive too much oil and the rear flange seal to leak.


What is a rebuilt engine?

A rebuilt engine is an engine that has had most of the larger lumps of rust scraped off with a paint scraper, some of the dirt and salt washed off with a garden hose, the crack in the cylinder head patched with JB Weld, everything (including the spark plug leads and flame arrester air intake ) painted any old colour with left-over cans of house paint, the old oil topped up with a mixture of Marvel Mystery Oil and STP, fitted with lawn mower spark plugs and 4 foot spark plug wires from an old V8 Chevrolet, a cheap gate valve installed in the thermostat bypass hose, initially started with a spray can of starting fluid after sitting outside with a tarp over it for several years, and advertised as "...completely rebuilt Universal engine, fresh-water cooled, like new, 2 year warranty, see it running, call Midnight Marine Supply - pager 999-9999"...

No, actually a rebuilt engine is an engine that has been completely dissassembled, professionally stripped in industrial acid and hot tanks to remove paint, oil, dirt, cooling system / water jacket deposits, and then measured, machined, and reassembled with new parts so that all clearances are within the manufacturer's tolerances, and all normal wear parts such as seals, bearings, gaskets, filters, hoses have been replaced. At a minimum, rebuilt engines should have the valves and valve seats ground using valve and seat grinding machines (not grinding paste), the cylinder bore ridge removed, the cylinder bore honed to a cross-hatch finish, the piston rings replaced, and the crankshaft bearings replaced. The engine cylinders should be rebored or sleeved and new pistons fitted if the cylinder bore is worn beyond manufacturer's tolerances.


My friend says when an Atomic Four engine is being rebuilt it should always be bored to the next oversize and fitted with new oversize pistons. Is he right?

No. Pistons for Atomic Four engines are expensive, and since most engines were raw water cooled and all engines are now at least 20 years old, corrosion in the water jackets may have reduced the thickness of the cylinder wall. Boring the cylinders oversize may reach a small pinhole caused by corrosion to cause a coolant leak into the cylinder. If the cylinder bore is worn beyond the limit for taper or ovality, it is usually better to install cylinder liners, which will retain the original cylinder wall thickness and may allow the use of the old pistons (if the ring lands are still in good condition) because the new liners can be sized to compensate for any piston skirt wear, and thus return the cylinder/piston clearance to the original specification.


My friend works in an automotive machine shop, and she says that when any engine, including an Atomic Four engine, is being rebuilt the pistons should be installed with the arrow mark and "Front" stamp on the piston crown pointing to the front of the engine... the front on an Atomic Four being defined as the flywheel end, not the marine gear/propeller shaft coupling end. Is she right?

No. An OEM Atomic Four piston top is marked with an arrow and the word "Front", but must be installed with the arrow pointing to the rear/marine gear end to in order to have the correct side of the piston (the side without the vertical expansion slot) in the thrust position. Pistons installed backwards cause mysterious oil consumption problems after an engine rebuild.


My friend says when an Atomic Four engine is being rebuilt the camshaft bushings must always be replaced. Is he right?

No. In order to properly clean an engine for rebuilding it must be cleaned in an industrial "hot tank", which requires that the camshaft bushings be removed (to prevent them from being damaged by the caustic cleaning solution) and then reinstalled and line reamed as part of the assembly process. Atomic Four camshaft bushings wear very little unless the engine has experienced a lubrication failure at some time in the past, and because they are expensive it is considered cost-effective to re-install them even when the engine is being completely rebuilt and all other bearings are being replaced.


Do I need a tachometer?

No, a tachometer is not essential, although it is a popular accessory. A tachometer should be used initially to verify the correct propeller has been fitted, but once that is done engine speed is limited by maximum boat speed, and is directly linked to the boat speed shown by the boat knotmeter, so a tachometer is not essential. Engine speed may be higher than normal in case of transmission clutch slip, a sheared propeller shaft flange or propeller key, a damaged diesel engine governor, or a damaged propeller, however excessive engine speed will quickly be recognized by a marked increase in engine noise and vibration.


I got the UAP-NAPA numbers for Atomic Four tune-up parts off the internet, but my local UAP-NAPA auto parts store says they can't use them. Why not? (PS I live in Canada.)

Canadian UAP Napa part numbers are different from the American numbers given on American news groups and Atomic Four web sites. You don't need the numbers for most parts. Just tell the counter sales representative at any good auto parts store that you want parts for a Universal (Westerbeke) Atomic Four marine engine, model UJ, and they'll look them up (or order them from Atomic Four Engine Service).


How do I pick the right gauge and gauge sender?

Most electrical gauges except voltmeters and ammeters work in tandem with a variable resistance gauge sender. In order for the gauge to read correctly, the sender has to be matched to the gauge. There is no industry standard gauge sender resistance, and each manufacturer uses their own specification and design, so gauges and gauge senders from different manufactures usually are not compatible. As well, each manufacturer makes different resistance gauge senders for boats with single station controls and for boats with dual station controls (1 sender connected to 2 gauges) which cannot be interchanged. The wrong sender can instantly destroy a new gauge, or fail to warn the operator of an engine problem. For those reasons it is recommended that oil pressure, water temperature, exhaust temperature, manifold vacuum, fuel pressure, water pressure, etc. gauge senders be replaced at the same time gauges are replaced.

Cheap gauges usually work OK for a while, but are usually are not properly designed to withstand the vibration and corrosion inherent in marine use and break just when they're needed. The flimsy mounting systems on cheap gauges usually cause more lost time than was saved in not buying a quality product too, as well as causing a lot of problems with loose gauges and wires. For those reasons, and more, we only sell Stewart Warner (SW) marine gauges and senders, because we find that their initial higher cost is more than compensated for by their faster installation, reliability and accuracy.


Are Atomic Four engines dangerous because they use gasoline for fuel?

No. Gasoline vapour is highly inflammable and can cause an explosion if it ignites in a closed space like the engine compartment or cabin of a sailboat, however if the fuel system is properly installed, the engine and fuel system receive regular maintenance, and the operator follows Canadian Coast Guard safety procedures when refuelling, gasoline causes few problems. We are only aware of one Atomic Four gasoline vapour explosion which caused a fatality (in Montreal several years ago), despite the fact that there are thousands of Atomic Four equipped sailboats still in use. There are also thousands of inboard/outboard motor boats fitted with gasoline engines in use too (ie Mercruiser), and although explosions and fires are not common, they happen frequently enough to keep Atomic Four owners nervous.

The propane gas used on many boats for cooking and heating is similar to gasoline. Both gasoline and propane vapours are explosive and heavier than air, and so collect in the lowest part of the boat, which is usually where the engine is located. The Canadian Coast Guard Fire Safety Pamplet suggests that inflammable vapours are usually ignited during starting by the spark created when the starter bendix gear hits the flywheel ring gear, so even though diesel engines do not have an ignition system which creates a spark like those used on gasoline engines, diesel powered boats fitted with defective propane systems are just as susceptible to an explosion during starting as gasoline powered boats with a defective fuel system.

Gasoline engines like the Atomic Four are perfect for coastal cruising because they are smooth, quiet, and easy to maintain. They're also free of the nausea inducing smell of diesel fuel (important if there are children on board) and it's easy to find fuel because gasoline is a standard fuel everywhere. For off-shore cruising the diesel engine is the best choice because of it's range and reliability (if it's properly maintained).


What is the right way to hire an marine engine repair technician/mechanic?

Engine problems/failures are usually the result of a poor preventive maintenance program, and quite often occur to engines which have not had a major tune-up / inspection in years. Before spending a lot of time and money diagnosing one mysterious problem after another, make sure the engine has had a recent major inspection/tune-up/service as per the engine service manual preventive maintenance program... and if it hasn't, perform one right away.

When a mechanic is being contracted to work on your boat ask for proof of mechanic's license, liability insurance, and workers' compensation board registration before letting he / she on board. Get a written quotation for the work you want done. Clarify the tax status of the mechanic, and what taxes you will be paying. If the mechanic offers to work for cash to avoid any tax record, remember that a person who offers to make an arrangement to avoid paying provincial and / or federal tax is obviously not honest, and will be just as quick to steal from you as they are to steal from the government. Without a receipt for the work there is no tax record, but there is also no record of the work being done in the event of legal or warranty issues. Check to make sure the mechanic has a full set of professional tools... cheap, poorly made tools are the mark of an amateur. Make sure the mechanic fills out a work order form with your written instructions recorded on it, and that he/she understands that all the parts replaced must be retained for your inspection. Do not talk to the mechanic while he/she is working on your engine except to ask questions regarding the condition of the motor and point out components or problems you would like the mechanic to inspect/repair. Do not ask to borrow tools or read manuals while the work is in progress. Before the mechanic starts work remove articles blocking access to the interior of lockers or the engine compartment. Be ready to pay the amount owing as soon as the work is done.


Is it a good idea to convert my engine to fresh water cooling by fitting a heat exchanger?

Yes. The cast-in water jackets in the cylinder block, cylinder head, and exhaust manifold of raw water cooled engines run in salt water are gradually being corroded by the salt water even when the engine is stopped, and plugged by the minerals and salts precipitated out of the hot water as the engine is run. Usually the first problem that occurs is overheating because the partially plugged water jackets restrict the flow of cooling water, and then later the engine block, cylinder head, and exhaust manifold begin to corrode through until they are so weak small leaks or cracks develop. Although cylinder heads and exhaust manifolds can be replaced, it is very expensive to replace the engine block itself (Atomic Four engine blocks are no longer available). The cost of all the components necessary to convert an engine to fresh water cooling is approximately $900, and although the conversion is expensive, it is one of the few modifications you can make to your engine that will actually increase the value of the boat, since it is quite common to see a boat with a fresh water cooled engine advertised at $500 to $1,000 more than the same model/year/condition boat with a raw water cooled engine.

When a raw water cooled engine is converted to fresh water cooling, the existing water pump (usally driven directly off the engine from an engine auxiliary drive) is usually used as the engine coolant pump to pump the water/antifreeze coolant through the engine, to the heat exchanger, and back to the engine. 2 types of heat exchanger can be used, a horizontal engine mounted heat exchanger mounted over the exhaust manifold or at the rear of the engine over the marine gear, or a vertical remote heat exchanger mounted on an adjacent bulkhead. Universal diesel engines after the Model 5416 were equipped with fresh water cooling as standard equipment, with the sea water pump driven by a power take-off on the front of the engine. The engine coolant pump on most models is a centrifugal belt driven automotive type water pump. Universal Atomic Four engines were available with an optional fresh water cooling system which used a horizontal heat exchanger mounted over the exhaust manifold and a sea water pump mounted over the starter and driven by a belt from a pulley on a power take-off assembly mounted on the front of the flywheel. Aftermarket heat exchanger kits mount the sea water pump in various locations: over the starter in the same configuration as the OEM system, over the alternator and driven by a longer alternator belt which also still drives the alternator, directly off the front of the engine using a rubber cush drive assembly, and an electric pump mounted in a convenient location near the engine or heat exchanger.


How do I adjust the ignition timing on an Atomic Four engine?

The ignition timing on an Atomic Four engine can be adjusted in several ways, but no matter which method is used, before the timing is adjusted the distributor should be serviced to make sure the distributor shaft bushings are lubricated with light oil (a few drops of oil on the little piece of felt under the rotor) and not worn beyond specification, the centrifugal ignition advance is properly lubricated and working smoothly, and the contact breaker (points) gap is adjusted to specification using a feeler gauge, or a dwell meter if one is available. Once this is done the engine can be timed.

Static timing can be carried out by turning the crankshaft so #1 cylinder is at the very top of its stroke (TDC) with both valves closed (firing #1 cylinder), the distributor rotor is pointing at the distributor terminal for #1 spark plug, and the distributor points are just beginning to separate. You can connect a battery powered light or buzzer across the points to determine exactly when they open. When #1 cylinder is at the top of its stroke the split pin in the front of the crankshaft will be pointing straight up and down.

Dynamic timing can be carried out by either tying the boat firmly to the dock or taking it out an area where it can be run at top speed for several minutes, connecting a tachometer to the engine, slightly loosening the distributor clamp screw, opening the throttle to get maximum engine speed, gradually rotating the distributor back and forth until the engine is running at the highest rpm possible, and then retightening the distributor clamp screw. At full speed the engine should reach at least 1,800 rpm (if it can't, see "What size propeller should I use?" above).


How do I adjust the carburetor on an Atomic Four engine?

Early model Atomic Four engines were fitted with a cast iron Zenith 61 carburetor with 2 adjustment screws, one for the high speed main jet, and another one for the low speed idle jet. Atomic Four engines after 1968 were fitted with an aluminum alloy Zenith 68 carburetor with a fixed high speed main jet (some Zenith 68 carburetors have had adjustable main jets installed), but the same adjustable low speed idle jet as the Zenith 61. Assuming the flame arrester is not partially blocked by dirt and oil, and the carburetor is clean and in good condition with the float level set properly, the proper procedure is as follows:

Carburetors with fixed high speed main jets should have the main jet removed and checked to see what jet number it is. The jet number is stamped in very tiny numbers on the face of the jet. If it is not a #21 main jet, it should be replaced with one.

To adjust the idle mixture screw, initially adjust the idle mixture screw (the upper adjustable jet with the slot for a screwdriver) clockwise (in) until it bottoms lightly, and then out 1 turn. Connect a tach to the engine, start the engine, run the engine in gear until it is fully warmed up, then close the throttle, leave the engine in forward gear, and adjust the carburetor idle speed screw (the screw on the carburetor throttle arm that controls the throttle stop) until the engine is idling at 700 rpm, turn the idle mixture screw slowly out until the rpm drops noticeably, and then in again until the fastest idle speed is obtained. Readjust the idle stop screw to again set the idle speed at 700 rpm. Repeat the idle mixture adjustment again.

Carburetors with adjustable high speed main jets should be initially adjusted by turning the main jet adjusting screw (the lower adjustable jet with the little cross on the adjustment screw) clockwise (in) until it bottoms lightly, and counter-clockwise (out) 3 turns, and the idle mixture screw (the upper adjustable jet with the slot for a screwdriver) clockwise (in) until it bottoms lightly, and then out 1 turn. Connect a tach to the engine, start the engine, and with the boat running at top speed in forward gear (or tied to the dock) slowly turn the high speed mixture screw clockwise (in) until maximum rpm is obtained on the tachometer and then counter-clockwise (out) about 1/8 of a turn until the rpm just starts to drop.

Close the throttle, leave the engine in forward gear, and adjust the carburetor idle speed screw (the screw on the carburetor throttle arm that controls the throttle stop) until the engine is idling at 700 rpm, turn the idle mixture screw slowly out until the rpm drops noticeably, and then in again until the fastest idle speed is obtained. Readjust the idle stop screw to again set the idle speed at 700 rpm. Because the idle mixture setting has an effect on the main jet setting, repeat the main jet adjustment, and then the idle mixture adjustment 2 more times.

The rationale for setting the idle speed at 700 rpm in forward gear is to ensure the engine is idling fast enough to prevent stalling or erratic running when docking. An engine speed of 700 rpm in gear will also automatically increase to about 800 rpm when the transmission is shifted to neutral, which is high enough to allow the alternator to continue charging the battery.


Some people say the Atomic Four takes 2 head gaskets, and some say it only takes 1. Who is right?

Both are right. 2 head gaskets (Universal #23776) were specified for the Atomic Four from its introduction until Westerbeke released a new graphite gasket (Westerbeke/Universal #200452) in 1996. The technical bulletin released with the new gasket specified only 1 of the new gaskets is required, however the manufacturer of the gaskets, Victor Gasket, specifies that 2 gaskets are to be used, as do several American Atomic Four specialists (ie Don Moyer). Our tests suggest that 1 gasket works fine, however 2 gaskets probably work well when the cylinder head gasket surface has been machined several times because using 2 gaskets helps lower the compression ratio slightly, which is a good thing in flathead marine engines like the Atomic Four. Refer to Universal Service Bulletin 223 for more information.


There are a lot of accessories available for the Atomic Four. Which ones should I buy?

Many people will spend a lot of money on cheaply made accessories for their boat and marine engine, but skimp on basic maintenance and regular overhauls. We recommend purchasing a heat exchanger and suggest the Indigo Electronics PCV valve kit is a good short-term fix for an engine that needs a ring job and is smoking up the cabin, but don't recommend an accessory oil filter, an electronic ignition, or an adjustable thermostat bypass valve.

Accessory oil filters are not full-flow filters which filter all the oil before it is pumped to the bearings like the type used on cars, but are bypass filters which filter a small portion of the oil at a time. Changing the oil regularly achieves the same thing, without the possibility of the external oil lines to the accessory oil filter breaking or leaking, and causing massive engine damage.

Electronic ignition is not required on a slow-running engine like the Atomic Four, since the standard points and condenser can easily produce enough voltage to fire the spark plugs at any speed and load. As well, since the distributor cap must be removed on a seasonal basis for lubrication of the shaft and advance mechanism, it is a simple matter to install a new set of points and a condenser at the same time.

An adjustable thermostat bypass valve makes the Atomic Four have that "vintage" engine look, but is completely unnecessary if a functioning thermostat of the correct temperature rating to suit the engine is fitted to a properly tuned engine that has reasonably clean water jackets, a properly functioning water pump, and (in the case of a post 1968 Atomic Four) a thermostat housing with a bypass port boss which is in good condition. If there is a need to restrict the bypass hose with an adjustable valve to prevent overheating, the engine and/or the thermostat or thermostat housing should be repaired/replaced.


How should I prepare my Universal engine for below freezing temperatures?

Boats sink on the first warm day of spring because the owner made 2 mistakes at the same time. He/she failed to close the engine sea water through-hull sea-cock when the boat was left for the winter, and water was allowed to freeze in the sea-water side of the engine cooling system, which ripped a section of the sea-water hose or cracked an engine cooling system component. Once the ice melted it allowed sea-water to flow into the boat through the open valve and the damaged hose or component.

Remembering to close the sea-cock but failing to properly freeze-proof the engine will likely mean only massive engine damage and not a boat full of cold water too.

If you live in a place where there is any chance the temperature could go below freezing during the winter, you need to freeze-proof your engine before winter weather arrives to make sure the engine and components are not damaged by freezing temperatures. There are 3 ways to ensure water can't freeze in the cooling system and crack or distort engine components. You can drain all the water out of the cooling system so there isn't any water to freeze, you can circulate antifreeze through the cooling system so the water in it can't freeze, or you can use heaters to keep the engine and cooling water system warm enough so they don't freeze.

Draining: Even if drains can be opened without snapping off a seized drain plug, they frequently are hard to get at, and they quite often get plugged up with bits of rust and dirt which stop the flow of water when they are being drained, giving the impression the component is empty when it is not. If water is not completely drained from every section of the cooling system it can cause freezing damage in one or more individual sections which may not be evident until years later when the component fails.

Adding antifreeze: The optimum solution for maximum engine antifreeze protection (good to -60C) is 60% ethylene glycol antifreeze and 40% water. In order to ensure an engine cooling system is properly protected the antifreeze solution must be cirulated to every part of the engine water jackets, heat exchanger, water lock exhaust or water jacketed exhaust pipe, and sea-water intake valve, strainer, and hoses. Because it is possible for the antifreeze to reach only some of the engine water jackets unless the engine is fully warmed up and the thermostat has opened, it is necessary to rig up a system to recirculate the antifreeze solution through the engine while the engine is running while the engine grows hot enough for the thermostat to open, or to remove the thermostat before circulating the antifreeze.

Heaters: Heaters work well, as long as they are capable of maintaining the engine, engine coolant hoses, exhaust system, and through-hull valve at a temperature higher than freezing, and as long as nobody pulls the plug or causes a power failure. In latitudes north of Florida using a light bulb for a heater is asking for trouble, since the light bulb doesn't put off enough heat to prevent freezing damage when temperatures start to go below -10 C. If a heater is going to be used, make sure it is connected to a temperature switch so it will turn on automatically when the temperature drops close to freezing, and that it can actually keep the engine and coolant/exhaust system warm. Ensure that the power supply is very reliable, and that a backup heater is available.


Should I carry a spare parts kit on my boat for my engine?

Yes, a new Universal Atomic Four or Universal diesel spare parts kit is available from Westerbeke/Universal. It comes in a nice waterproof plastic box labelled "Universal". In order to save a bit of money most people make their own by assembling good used parts and some new ones. I recommend spare assemblies where possible, not just a bunch of parts, since the correct tools to rebuild assemblies are not always available (ie vice, press, parts washer, etc).

On my own boat I carry:
rebuilt starter
rebuilt alternator
water pumps (I have a heat exchanger, so I need 1 sea water pump, and 1 engine coolant pump)
2 spare alternator belts
2 spare sea water pump belts
rebuilt carburetor (gasoline engine) or rebuilt fuel injectors (diesel engine)
electric fuel pump and mount
2 metres of rubber fuel hose and some fuel hose clamps
1 set of engine coolant hoses and some clamps
1 set of sea water pump hoses and some clamps
exhaust hose clamps
rebuilt distributor
set of spark plugs
set of spark plug wires
distributor points, condenser, rotor, cap
3 fuel filters
6 litres of engine oil
4 litres of transmission (marine gear) oil
1 litre of V drive hypoid gear oil
complete gasket set
a box of fuses (6 per box) for each type of fuse on the boat
3 or 4 light bulbs for each type of bulb on the boat
a box of miscellaneous nuts, bolts, washer, screws, pipe fittings, cotter pins, roll pins, allen screws, rivets, etc
JB Weld
3M 5200 sealer
penetrating oil
stainless steel lock wire
electrical tape
miscellaneous electrical wire & terminals
a couple of small lengths of 2" x 4" wood
set of hand tools, electric drill and drill bits, electrical tester, propane torch, hack saw, axe, big cable cutters, etc


A friend told me that Atomic Four engines sometimes have erratic oil pressure, and there are several ways to fix the problem. What is he talking about?

Erratic Atomic Four oil pressure is a problem caused by Universal's change of the adjustable oil pressure regulating valve internal parts to a spring and 3/8" ball from a spring and pencil-shaped plunger around 1965 - 67. [Check yours and if you have a ball measure it to determine if it is .375" (3/8") or 7/16" (.438")]. The spring and ball was not as good at controlling the oil pressure as the old spring and pencil-shaped plunger so they started using a larger 7/16" ball around 1972. This still didn't always work, and so they released a retrofit kit which was actually the old spring and pencil-shaped plunger. The kit was accompanied by a service bulletin titled "Atomic Four - Installing Oil Pressure Plunger Kit #256575" which is in the Atomic Four Parts Manual on page 98A/B and details a procedure called "seating plunger or ball" which can be used to improve the performance of the existing ball or when a pencil-shaped plunger is installed.

Dangerously high oil pressure (ie over 60 psi) when the engine is first started in cold weather may be alleviated somewhat by using SAE 10 - 40 oil rather than SAE 30. We recommend the use of 10 - 40 oil year round in any case, however it is most beneficial in cold weather.

The text of the service bulletin is copied on this web site at http// . The graphics portion of the service bulletin will be added when I get more web space.

Once you've got the ball or plunger installed and seated, adjust the oil pressure to 35 psi at cruise speed rpm with the engine hot.


A friend told me that there is no difference in operating an Atomic Four engine and a diesel marine engine, and top speed on boats fitted with either type of engine is obtained by moving the throttle lever all the way to full open and leaving it there. Is he right?

No. Unlike diesel marine engines the Atomic Four does not have a governor, and so the operator has to set the throttle manually according to the forces acting on the boat (ie head winds) at a setting which gives a maximum of about 90% maximum boat speed, (assuming the propeller is the correct size). Since top speed is determined by hull waterline length, and no amount of horsepower can get the boat past it, all any extra throttle does is overload (lug) the engine. To determine the correct throttle setting for maximum cruising speed, open the throttle wide open for a few minutes and record the boat speed from the knotmeter (or GPS). Then after that use only enough throttle to run at about 90% of the top speed obtained with wide-open throttle. For example if the maximum speed of the boat is 7 kn, then open the throttle only far enough to give a cruise speed of around 6 kn.


A friend told me that low engine operating temperature is a sign of a defective thermostat. Is he right?

Sometimes it is. Low engine coolant temperature which persists after the engine has been run under load for an appreciable length of time means either a missing thermostat, a defective gauge/sender, or (in cold water) a sticky or poorly sealing thermostat. You can check the actual water temperature by holding a portable surface thermometer against one of the middle cylinder head studs. It will read the real cylinder head water temperature, which is the temperature the gauge should read if the gauge and sender are properly calibrated and working correctly.

The large single spring fitted to the new Atomic Four thermostat supplied by Westerbeke has less pressure than the 3 small springs used on the OEM Holley thermostat originally fitted on engines made after 1968. If there is any restriction in the bypass line and/or a higher pressure Oberdorfer M7 (full cam) water pump has been fitted, the pressure developed by the water pump will actually overcome the force of the spring and open the thermostat slightly when the engine is cold. This can cause the engine to take longer than usual to warm up to operating temperature, as well as causing engines being operated in very cold water to run colder than the rated thermostat temperature.


How do I measure a used crankshaft to make sure it will fit my engine?

A crank or rod is more likely to break if the engine is over-reved in neutraul rather than if the prop is too big; ie the boat is running in neutral and the throttle cable breaks or jams (or somebody steps on the throttle lever... which promptly breaks off in the wide-open position!), so the carb goes to full throttle and the engine tries to imitate an out-of-control chainsaw.

If you're checking a bunch of used cranks to see if you can find a good one, you don't want to have to install each one in a block and check the clearance with plastigauge, that could take a lot of time and require carrying a block around... and you could get a plastigauge measurement over .0025" (the maximum bearing clearance specified by the factory) on a good crank if a main bearing cap is oval and the block actually needs to be line bored, or if the crank is good but the bearing insert is worn.

You can quickly check to see if the crank journals have been damaged from wear or a seized bearing by scraping them with a small piece of copper (a penny will work). If any copper wears off on the journal it is not smooth enough, and must be reground. If there are any knicks or rough spots that also means the crank must be reground.

If the journals pass the penny test, then measure each one with a micrometer, taking at least 4 measurements... 2 at one position on the journal at each edge, and another 2 more at 90 degrees to each other on each edge. That way you can tell if the journal is worn oval or tapered, and you can also tell if the crank has already been ground undersize (a lot of people think that Atomic Four cranks tend to break if they're ground undersize, and will only use a crank with standard size journals... I'm not one of them, the factory specified undersize grinding, and so far I haven't found anything that they didn't do right, so I don't see why they would be wrong here).   For example, the Atomic Four engine main bearing journal standard size dimension specified in the service manual is 1.9880", +.0005" / -.000", which means each journal must not be worn oval or tapered more than .0005", as well as being the correct size so it will fit the bearing. If the journal is not oval or tapered more than .0005", but it is over 1.9885", then it is too big (not very likely unless the crank was built up with weld and not machined back to the correct size), and if the journal is under 1.9880" it is too small (probably from wear... but also not very likely that it wore perfectly round, since there is more pressure on the bearing and journal in some positions than in others). Usually the crank was originally the right size and has gradually worn oval, so one measurement will read around 1.9880" and the other measurement (in the position of highest pressure) will read around 1.986" or 1.987", meaning the crank is worn oval about 1 or 2 thousands of an inch (which is impossible to see with the naked eye). But it doesn't really matter whether it has worn large, small, tapered, or oval... if any of the micrometer readings of a standard sized main bearing journal are under 1.9880" or over 1.9885", then the crankshaft cannot be used without the main bearing journals first being machined to bring them within specifications (and new bearings of the correct size fitted). The same goes for rod bearing journals, except all measurements on them must not be under 1.5620" or over 1.5625" (for standard size journals).

All crank journals should be micro-polished to a mirror-like finish before the crankshaft is installed. You can do it yourself with strips of 600 grit wet/dry sandpaper the width of the journal dipped in parts cleaning fluid and spun around the journal with a boot lace.   Even if the crank journals are in good condition and within specification, a used crank that was found in a pile at the back of a shop some place and not taken from a running engine should be checked to make sure it is not bent and it doesn't have any cracks by an automotive machine shop before being installed (to make it perfect you can also have the machine shop balance it, but for that you also need to bring them the rods and pistons/piston pins/piston rings you are going to use) .


I just bought my boat last year, and recently a friend asked me what I would do if my Universal engine quit suddenly... and I didn't know what to tell him! Another friend told me that sailboats are supposed to sail, and that it doesn't matter if the engine quits... a real sailor only uses the engine to charge the batteries and leave the harbour (although he's from Europe and has never sailed in a place like this, where there are heavy tides and currents, and many people keep their boats upstream on big rivers). After thinking about it I realized an engine failure in some situations could be very scary for my family, and it worries me all the time now when I use my boat... I'm constantly listening to the engine and worrying about it stopping, and it's taking the fun out of the whole thing to the point I don't even want to use the boat.

If you live upstream on a big river like a lot of us do an engine in a sailboat isn't a luxury as some suggest... without one we can't get home... and can't steer! I went through lots of horrible scenarios after I bought my boat... finally deciding the worst case would be the engine quitting while I was on the inside of a bend of a river and the current quickly pushing the boat down between a huge tugboat connected to a giant barge of woodchips with a heavy steel towcable.

Initially I actually fitted an outboard mount on the transom of my Hughes so I could fit the dinghy outboard if the Atomic Four quit, but it looked so horrible I removed it a month later, after I realized it would take me a lot longer to place the outboard on the mount and get it started than it would take a tugboat to tow a barge over my boat.

I decided to prepare in advance for the hypothetical "worst case" engine failure I might face in my sailing area, and plan a response to each part of the scenario:

1. Travelling upstream on a large river with a heavy current in the dark on a rainy night and the engine and navigation lights quit suddenly while I'm on the inside of a bend ... the boat immediately starts drifting backwards into the middle of the river.
Cause: My boat has a major electrical and engine failure.
: Prevent engine and lighting failures (most engine failures are caused by electrical or fuel problems) by performing regular maintenance as per the engine owner's manual, fitting a good water separator, and upgrading the engine wiring harness and alternator/battery cables/batteries.

2. The boat drifts directly towards the path of a large commercial vessel that isn't changing course.
Cause: The commercial vessel doesn't know I have suddenly starting to drift towards it because I haven't sent it a message, which is why it doesn't alter its course to avoid me. I can't send it a message; the fixed VHF radio doesn't work because it is connected to the boat's electrical system, which has failed.
Action: Keep a waterproof fully charged portable battery powered VHF radio and spare batteries on board.

3. Even if the fixed VHF radio did work, or I had a battery powered portable, it would be down in the cabin and I wouldn't want to leave the tiller to go down and get it.
Cause: The VHF radio is not accessible without leaving the tiller.
Action: Keep a waterproof fully charged portable battery powered VHF radio and spare batteries in the cockpit.

4. Even if I had a portable VHF radio in the cockpit I wouldn't remember what channel commercial vessels monitor.
Cause: I don't have a placard handy which shows the correct channels for making VHF radio calls to commercial vessels.
Action: Keep a placard with the portable VHF radio which shows the correct channels for making VHF radio calls to commercial vessels.

5. I cannot steer the boat away from danger... the other oncoming vessels and the rocks on the outer bank of the turn in the river.
Cause: Without a source of power I have no forward motion and cannot steer.
Action: Sailboats have an alternate source of power besides the engine. When motoring in the river keep the mainsail up or ready to raise immediately in order to be able to immediately attempt to sail out of danger.

6. The boat is drifting into the path of other boats travelling up and down the river who can't see it and therefore are not altering their course to avoid it.
Other boats cannot see me because my boat has no lights.
Action: Keep several waterproof fully charged battery powered flashlights in the cockpit. Change the batteries regularly to make sure they'll work when needed in an emergency.

7. I need to stop the boat right away to keep from drifting into danger, and so I can leave the helm to diagnose/repair the problem. It takes a couple of minutes to deploy the bow anchor, and if I'm alone I can't leave the stern tiller to deploy it while continuing to use the radio and keep watch, and trying to steer a bit.
Cause: I have no permanent way to stop the boat without leaving the tiller.
Action: Fit a good stern anchor ready for instant deployment, so it can be deployed without leaving the tiller. Make sure it is mounted permanently and securely so it can be left in place in rough weather without swinging and causing a hazard, or self-deploying, but can be easily deployed in the dark.

8. It's so dark I can't see across the big river to the other side so I can select a good place to deploy the anchor and avoid hitting the rocks I know are there.
I can't afford radar (it would be out of service anyway due to the electrical failure), and I don't have the ability to see in the dark.
Action: Carry a night vision scope on board, they're a lot cheaper than radar, and easier to use in an emergency.

9. Once the boat is stopped and out of immediate danger, I need to call for assistance and/or a tow home 24 hours a day.
Cause: I don't know who to call for help.
Action: Call at least 2 local marine assist companies during office hours and ask the manager to explain how to call them for assistance, what hours they provide sevice, what services they provide, what they charge, and if they require a credit card before starting a tow.

10. If I was ready to call for assistance I wouldn't know the numbers to call.
Cause: I don't have the numbers or radio call signs to call for help someplace where I can find them.
Action: Keep the phone number & radio call sign for the local marine assist companies you decided to use, as well as the numbers to contact the Coast Guard, posted on the boat in a prominent place where they can be found easily in the dark.

11. If I was ready to call for assistance and they wanted payment in advance I wouldn't have cash or credit card to pay them.
Cause: I don't usually carry much cash or credit card on the boat.
Action: Carry a credit card and enough cash on the boat to be able to pay for help.

12. Once the boat is stopped and I could look at the engine and electrical system to try and repair the problem, I wouldn't have tools and parts.
Cause: I don't have tools or parts to repair common failures.
Action: Carry a set of tools and spare parts and engine manuals, so that I can make basic mechanical repairs.

13. I want to move the boat to relocate to a safer anchorage, a repair depot, or limp home.
Action: Carry or tow a dinghy and matching outboard engine, and a set of lines or straps which can be used to strap the dinghy beside the rear quarter of the boat to "push" it. Configure the outboard engine so it can be fixed in the straight-ahead position with the throttle set on high speed. Test this setup before it is actually needed. Carry enough emergency fuel for the outboard engine in a separate container to give it a reasonable range even if the tank on the engine is empty.


I removed my distributor to clean it, and although I marked the direction the rotor was pointing before I removed it, I forgot to mark the way the distributor itself was installed. Then, while the distributor was out my friend accidentally hit the starter button and turned the engine over. Now the spark plug wires don't fit properly and the engine pops in the carburetor and won't start... so I guess the distributor AND the rotor are in wrong. How do I reinstall the distributor and rotor correctly so the spark plug wires fit and it has the correct ignition timing so the engine will start?

The Atomic Four has a firing order of 1 2 4 3, and the crankshaft is designed so that pistons #1 and #4 go up and down together (and so do pistons #2 and #3, but 180 degrees out... when pistons #1 and #4 are at the top together, pistons #2 and #3 are at the bottom together). The reason to know this is that when piston #1 is at the top its firing stroke... firing #1 cylinder, piston # 4 is at the top of its exhaust stroke and just starting to do down on its intake stroke... with the exhaust valve just closing and the intake valve just opening, AND YOU CAN SEE PART OF THE INTAKE VALVE FOR #4 CYLINDER TO DETERMINE WHEN IT IS JUST STARTING TO OPEN BY LOOKING STRAIGHT DOWN #4 SPARK PLUG HOLE (IT'S THE ONLY VALVE YOU CAN SEE LOOKING STRAIGHT DOWN).

So, remove the spark plug for #4 cylinder (it's easier if you remove all the spark plugs) and turn the engine by hand in the direction of rotation (counterclockwise facing the flywheel) while looking straight down the #4 spark plug hole with a flashlight (if you can't look straight down the plug hole use a little piece of wood such as a popsicle stick to feel the valve going up and down). As the engine turns you will see the intake valve in #4 cylinder rising and falling. Carefully turn the engine over and stop just as you see the #4 intake valve just starting to open. That will mean #1 cylinder is now at the firing position, so remove the distributor and install it so both the rotor and the wide protrusion in the side of the distributor points plate (which fits into a slot in the distributor cap to align it) both point at 9 o'clock (looking down on the top of the distributor facing the flywheel). Once the distributor is in leave the distributor clamp loose, and install the cap, spark plugs, and spark plug wires, making sure the plug wire for #1 cylinder goes in the 9 o'clock postion, #2 plug wire goes in the 12 o'clock position, #4 plug wire goes in the 3 o'clock position, and #3 plug wire goes in the 6 o'clock position. Once the engine starts turn the distributor slightly back and forth so it runs the fastest. When everything is back in place time the engine at full speed as per the section on timing above.


I'm responsible for the maintenance of 2 charter sailboats, one with a Universal Atomic Four, and one with a Universal M25-XPB diesel. The owner's manual for the Atomic Four engine says the oil should be changed every 50 hours, and the owner's manual for the M25-XPB engine says the oil should be changed every 100 hours. How should I keep track of the engine hours, and does it make any difference if the hours are spent idling or at full cruise speed? Neither engine comes with an hour meter on the control panel, so I guess I need to install one on each boat, eh?

Hour meters are a very inefficient way to schedule an engine preventive maintenance (PM) program, because measuring the hours of use does not take into account the load on the engine while it was running, and engine load usually directly corresponds with engine wear... and engine wear is what is used to trigger a much more precise predictive maintenance (PdM) program.

A measurement that does correspond to engine load... and therefore engine wear, is energy consumption, which can be tracked easily by keeping a record of fuel purchases (some people use a specific credit card for boat fuel only, so they can get a regular report of fuel consumption on their credit card invoice).

Before fuel consumption can be used to schedule maintenance for a specific engine/boat combination the average fuel consumption per hour at full cruise speed needs to be calculated, usually by filling the fuel tank to the top, running the engine for exactly 1 hour under full cruise speed, and then measuring the amount of fuel needed to refill the tank to the top again.

For example, most direct drive Atomic Four engines burn an average of 4 litres (1 US gallon) per hour at cruise speed, so oil changes should be carried out when the Atomic Four gas receipts total approximately 200 litres (50 US gallons).

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