How to Winterize a Yanmar Marine Diesel
Winterizing a Yanmar diesel engine is essential when removing the vessel from service, regardless of the season. The largest part of the winterization process involves ensuring the raw water system is drained of the water that's sucked up through the raw water valve in the "sea chest" -- the system of valves in the bilge allowing water to be drawn from the lake or ocean -- and flushing the system with antifreeze. Failure to take these steps may result in damage during storage.
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Things You'll Need
- Motor oil
- Oil and fuel filters
- Adjustable wrench
- Five-gallon bucket
- Anti-corrosive antifreeze
Instructions
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1
Change the oil and fuel filters. Remove the top of the primary fuel filters, replace the filter elements, fill the filter canisters with diesel fuel and replace the canister tops.
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2
Close the vessel's raw water seacock (the valve in the "sea chest") that supplies cooling water to the motor and water for the vessel's fire-fighting systems. Open the engine's water drains (located on the water lines), the exhaust manifold and the turbochargers.
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3
Disconnect the hose at the end of the pipe running from the sea chest to the engine's raw water cooling system inlet with an adjustable wrench. Attach the end of another, similarly sized hose to the engine's raw water inlet and set the opposite end of that hose into a five-gallon bucket of an environmentally appropriate anti-corrosive antifreeze.
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4
Push on the water pump drive belt to check its tension: It should depress no more than one-half inch. Start the motor and run the motor until antifreeze comes out of the exhaust system.
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5
Reconnect the hose from the raw water cooling system pipe to the engine's raw water inlet. Lubricate the valve in the sea chest with white marine grease and open it only if the vessel has been removed from the water temporarily.
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Tips & Warnings
Water expands as it freezes. Water is effectively incompressible; you can break an ice cube, but you can't compress one. Water freezing in the block of an engine is like putting a glass bottle of water into a freezer: The bottle cracks as the ice freezes.
