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General Information
Preparations For Starting
Before Starting
Starting Engine
Engine Break-in and General Running
Stopping the Engine
Decompression Lever
Instrument Panel
Wiring Diagram
Preparing Engine for Storage
Preparing Engine for Spring Service
Fuel Injection Timing
Diesel Valve Timing
Adjusting Fuel Timing
Decompression Device Adjustment
Fuel System
Fuel Bleeding
Oil Filter Change
Sea Water Pump and Impeller Replacement
Model 15 Sea Water Circulation Diagram
Model 12, 18, 20, 25, 25XP, 30, 40 & 50 Water
Fresh Water Circulation Diagram

Hurth Transmission
Periodic Service Chart for Engine
Marine Engine Warranty - Limited

Engine Specifications and Images
(by engine model)




Proper preparation of your engine for storage will avoid damage and minimize expense when again placing your engine in service.
NOTE: It is recommended that your engine be winterized by an authorized Universal mechanic or at least, a trained mechanic familiar with the engine and its options.

1. Before boat is lifted out of the water, run the engine until operating temperature is attained.

2. Stop engine after warm up and remove crankcase oil through the dipstick hole using hand sump pump designed for that purpose. Replace dipstick after oil has been removed or through oil drain hose if one is provided. The newer engines have a drain hose for changing crankcase oil.

3. Refill crankcase with new oil and replace filler cap.

4. Run engine again for about 5 minutes to distribute a protective film of clean oil to act as a rust preventive during storage.
TRANSMISSION: (See transmission instructions)

.1. Fill transmission completely with type AFT or DEXRON II transmission oil. You may just add to the existing oil or drain the old oil and completely refill with new transmission oil.

2. Be sure both drain and filler plugs are tight after draining or adding to the oil in the transmission.

3. Transmission is now ready for storage.

SEA WATER COOLING SYSTEM: (All Models Except M-15)

OPTION #1 (Dry Storage)

1. To drain sea water system, disconnect hose end at sea water pump that comes from heat exchanger.

Lower free end of hose to a point approximately level with the front engine mount. This will allow the sea water to drain from heat exchanger and hoses.

2. Loosen the 4 or 6 screws on the sea water pump cover plate. Tap the plate lightly to loosen it, this will allow pump to drain.

3. After pump has drained, apply a light coat of lubrication to protect pump and impeller during storage and replace cover.

4. Drain exhaust muffler and system separately. 

OPTION #2 (Wet Storage)

Repeat Steps 1, 2 and 4 of Option #1

1. Disconnect sea water inlet hose at sea cock shut off valve. BE SURE SEA INLET VALVE IS CLOSED FIRST.

2. After the inlet hose has stopped draining, place hose into a (2 Gallon) container of antifreeze. Start engine and run the two gallons on antifreeze through the system until the antifreeze comes out the exhaust outlet, stop engine and check item 4. Make sure you do not run out of antifreeze while engine is running.

3. You should now have antifreeze in sea water pump, hoses, heat exchanger and exhaust system.

4. If aqua-lift or pot type muffler is used, it is recommended to drain p~ to pumping antifreeze thru system and afterwards to prevent coolant from backing up into the engine.



1. Open the cylinder block drain cock on the side of the block where hose from water pump enters, and drain.

2. Loosen water pump cover plate, allowing pump to drain, lubricate and replace cover.

3. Remove drain plug or rear bottom of exhaust manifold, and drain.

4. When boat is out of water, inlet lines to pump and thermostat will drain. Close sea cock valve when completed for storage.

5. If aqua-lift or can type muffler is used, it is recommended to drain muffler and lines of water. 

OPTION #2 (With engine at operating temperature and stopped)

1. Shut off sea cock valve.

2. Remove hose at sea cock. Let water drain from hose. Place inlet hose into container of antifreeze (with decompression lever on). Crank engine over at 10 second intervals until antifreeze comes out exhaust outlet.

3. If aqua-lift or can type muffler is used, drain prior to pumping antifreeze thru system and afterwards to prevent coolant from backing up into the engine.

4. You may wish to do option -1 prior to -2 to insure all water is out of engine and exhaust system.

5. Replace hose to sea cock when complete. Be sure sea valve is closed.

6. Antifreeze will aid in coating inside of the engine, reducing rusting.


1. Remove pressure cap from manifold. (when engine is cool)

2. Open drain cock located above oil filter to drain engine block and head cylinder.

3. Open the in-line drain petcock located below the alternator. This will drain the manifold, heat exchanger and engine fresh water pump.

4. Remove 1/8" pipe plug at lower rear of manifold, to drain manifold separately.

5. Close all drain valves and petcocks when draining has been completed.

6. If antifreeze solution is used, it is not necessary to drain the system each year, providing you have the correct mixture to prevent freezing during winter storage.

1. Exhaust pipes and muffler should be drained of sea water. Allow the exhaust pipes to dry out. Seal exhaust pipe end to prevent entrance of moisture into the engine through exhaust valves that are open.

2. See Option -2 under Sea Water Cooling System appropriate for your model.

3. All can type mufflers should be drained after any long periods of cranking, as Sea Water pump will fill the muffler causing water to backup and enter the engine.

1. Remove battery and store it in a warm dry area.

2. Protect other electrical parts against moisture.

1. To protect against corrosion or moisture in the fuel supply tank, either fill the tank with fuel or drain completely and seal top securely for storage.

2. A diesel additive is recommended to prevent bacterial growth in the fuel.

You may want to completely cover the engine to provide additional protection. Care should be taken when covering so that electrical connections are not loosened and that fuel lines are not bent or broken.