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When an engine is to be stored or removed from operation for a period of time, special precautions should be taken to protect the interior and exterior of the engine, marine gear, and other parts from rust accumulation and corrosion. The parts requiring attention and the recommended preparations are given below. ‪

It will be necessary to remove all rust or corrosion completely from any exposed part before applying rust preventive compound. Therefore, it is recommended that the engine be processed for storage as soon as possible after removal from operation. ‪

The engine should be stored in a building that is dry and can be heated during the winter months. Where this is not practical, moisture absorbing chemicals are available commercially for use when excessive dampness prevails in the storage area. ‪

Store Marine Engine for Winter

Store the marine engine for winter as follows: ‪

  1. Prepare marine cooling system for winter storage as follows:
    1. Check the protection of the antifreeze. The solution of ethylene glycol-base permanent antifreeze should be sufficient to protect your engine from freeze-up during the coldest part of winter. The maximum ratio of antifreeze compared to water, used in high performance engines, should not exceed 50% antifreeze and 50% water.

      Note: An excessive amount of antifreeze adversely affects freeze protection and heat transfer rates.

    2. A non-chromate inhibitor is recommended for additional corrosion protection. Inhibitor level should be checked in accordance with manufacturer's procedures every 150 hours.
    3. Check all hoses and hose clamps. Worn hoses should be replaced.
    4. It is recommended that the cooling system be cleaned every 1,000 hours or four years.
    5. A good radiator cleaning compound should be used according to the instructions on the container.
    6. After the cleaning operation, rinse the cooling system thoroughly with fresh water.
    7. Fill the system with soft water, adding Detroit Diesel Power Cool or equivalent fully formulated, inhibited ethylene glycol-base antifreeze in the required concentration.
    8. Drain the raw water system.

      Note: Ensure that the raw water is drained from the lowest position in the system.

    9. If a Jabsco water pump is installed, remove the raw water pump cover and impeller.

      Note: The blade of the impeller bent against the cam may take a set (lose flexibility) during long storage time.

  2. Prepare marine lube oil system for winter storage as follows:
    1. Drain the engine crankcase.
    2. Install and tighten the crankcase drain plugs.
    3. Install new lubricating oil filter elements and gaskets.
    4. Fill the crankcase to the proper level with Tectyl 930A preservative lubricating oil or an equivalent 30-weight preservative lubricating oil meeting Mil-L-21260C, Grade 2 specification.


      Diesel engine exhaust and some of its constituents are known to the State of California to cause cancer, birth defects, and other reproductive harm.

      • Always start and operate an engine in a well ventilated area.
      • If operating an engine in an enclosed area, vent the exhaust to the outside.
      • Do not modify or tamper with the exhaust system or emission control system.
    5. Start the engine and allow to idle approximately 10 minutes or more to ensure complete lubrication of all the moving parts.
    6. Shut down the engine.

      Tectyl is a registered trademark of Ashland Oil, Inc. ‪

  3. Prepare marine fuel system for winter storage as follows:
    1. Top off fuel tanks to prevent water from entering the system from condensation.

      Note: If the boat is stored where water in the fuel tanks may be a problem, additives containing methyl carbitol or butyl cellusolve may be used.

    2. Follow additive manufacturer's usage and handling recommendations, and observe all precautions. Where biological contamination of fuel may be a problem, add a biocide such as Biobor JF, or equivalent, to the fuel.

      Note: When using a biocide, follow the manufacturer's usage and handling recommendations, and observe all precautions.

      Note: Isopropyl alcohol is no longer recommended due to its negative effect on fuel lubricity.

    3. Drain and replace fuel filters.
    4. Fill the fuel filters with #1 diesel fuel or pure kerosene.
    5. Start and operate the engine for approximately five minutes to circulate the clean fuel throughout the system.
    6. Shut down the engine.

      Biobor is a registered trademark of United States Borax and Chemical Corporation. ‪

  4. Prepare marine gears for winter storage as follows:
    1. Drain the oil completely and refill with clean oil of the recommended grade and viscosity.
    2. Remove and clean or replace the strainer and filter element.
    3. Refer to section for the exhaust caution before preceeding. Start and run the engine at 600 rpm for ten minutes to coat all the internal parts of the marine gear with clean oil.
    4. Engage the clutch, alternating from forward to reverse, to circulate clean oil throughout all of the moving parts.
    5. Shut down the engine.
  5. Prepare marine electrical system for winter storage as follows:
    1. Remove and clean the batteries and battery cables with a baking soda-water solution and rinse with fresh water.

      Note: Do not allow the solution to enter the battery.

    2. Add distilled water to the electrolyte, if necessary, and fully charge the battery.
    3. Store the battery in a cool dry place (never below 32F or 0C).
    4. Keep the battery fully charged and check the level and specific gravity of the electrolyte periodically.
    5. Loosen alternator and accessory drive belts.

      Note: Loosening of the belts will prevent sticking between the belt and pulley.

  6. Prepare marine air intake and exhaust system for winter storage as follows:
    1. Seal all engine openings, including the exhaust outlet, with a moisture-resistant tape. Use cardboard, plywood or metal covers where practical.
  7. Completely clean the exterior of the engine.
  8. Check for areas that show corrosion and touch up with spray paint.

Restore Marine Engine from Winter Storage

Restore the marine engine from winter storage as follows: ‪

  1. Restore the air intake, exhaust system, air box drains and crankcase vent tubes from winter storage as follows:
    1. Remove all the covers and tape from the openings of the engine.
    2. Check that the fuel tank vents are open, along with the openings that may have been closed off in the engine room during winter storage.
  2. Restore the lube oil system from winter storage as follows:
    1. Remove the drain plug and drain the preservative oil from the crankcase.
    2. Install the drain plug and tighten.
    3. Fill the crankcase to the proper level with the recommended grade of oil. Refer to section .

      Note: You may wish to change the lube oil filters, especially if they were not changed before winter storage.

    4. Remove the air silencers or air cleaners in order to rotate the turbocharger.
    5. Disconnect the oil pressure line to the turbocharger.
    6. Using an oil can, pre-lube the turbocharger bearings.
    7. While pre-lubing the bearings, turn the turbocharger by hand. Fill the turbo bearing housing cavity with approximately one pint of the recommended grade of engine oil.
    8. Reconnect the oil pressure line.
    9. Install the air cleaner or air silencer.

      Note: Where available, a pressure prelubricator may be used to charge the lube oil system prior to starting the engine.

    10. Remove the pipe plug from the engine main oil gallery and attach the prelubricator hose.
    11. Using a positive displacement pump set at 25-35 psi, pump in the recommended grade of engine lubricating oil.
    12. Disconnect the prelubricator hose, plug the main oil gallery hole and replace all components previously removed.
    13. After approximately 20 minutes, check the crankcase oil level.
    14. Add enough oil to bring the level to the full mark on the dipstick.
  3. Restore the electrical system from winter storage as follows:
    1. Charge the storage batteries and install.
    2. Securely fasten the cables in place.
    3. Tighten alternator belt to the proper tension.
  4. Restore the cooling system from winter storage as follows:
    1. Close all drains that were open on the raw water system.
    2. If previously removed, install the raw water pump impeller, ensuring the vane of the impeller is turned in the correct direction.
    3. Install the raw water pump cover using a new gasket.
    4. Remove the plug or zinc electrode on the suction side of the raw water pump.
    5. Prime the raw water pump to prevent the pump running dry. Pour in at least one pint of water.
    6. Install plug or zinc electrode and tighten.
    7. Check the level of the antifreeze and coolant inhibitors in the fresh water system.
    8. Check tightness on all hoses.
    9. Insure that the raw water inlet sea cocks are operable and are open.
  5. Restore the fuel system from winter storage as follows:
    1. Prime the system with clean diesel fuel.
    2. Rotate the engine 180 degrees.
    3. Prime the system a second time to ensure fuel has passed through the injectors.
  6. Restore the marine gear from winter storage as follows:
    1. Check the oil level in the marine gear.
    2. Marine gear oil filters may be changed if they were not changed before winter storage.
  7. On non-DDEC engines, ensure that the stop lever is working freely.
  8. Check the emergency shut-down system to ensure that the engine can be stopped under emergency conditions.
  9. While holding the stop button in, crank the engine, release the stop button allowing the engine to start.
  10. To prevent serious damage to the starter, do not crank the engine over 15 seconds at a time.
  11. After the engine has started, observe the oil pressure gage immediately.
  12. If there is no oil pressure indicated within 10 to 15 seconds, stop the engine and check the lube oil system.
  13. Increase the RPM to part throttle and no load for approximately five minutes, allowing the engine to warm up before applying a load.
  14. While the engine is running, check for coolant, fuel or lubricating oil leaks.
  15. Tighten and align connections where necessary to stop leaks.
  16. Operate the engine at idle, engaging the marine gear forward and reverse to ensure complete circulation of oil.
  17. Monitor the marine gear oil pressure.
  18. Shut down the engine, then check the oil level in the engine and marine gear.
  19. Check the level of coolant in the expansion tank.
  20. Fire off the engines for sea trial.
  21. Once the engines have reached operating temperature, again check for water, lube oil and fuel leaks.
  22. Check that the pressure line to the turbocharger is tight and that there are no leaks.
  23. Monitor the operating conditions of the engine at 1200, 1400, 1600, 1800, 2000 and full load RPM.
  24. Inspect the engines for corrosion. Where necessary, clean and apply spray paint.