Join Date: Mar 2007
Thanked 4 Times in 3 Posts
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You want to change the oil while the boat is still in the water. Warm up the engine, shut it down, pump out the old oil (through the dipstick opening), change the oil filter, add new oil, then take the boat for a nice run under power to fully circulate the fresh oil. If you have to start the engine again to move it for haulout, it will not harm anything. The idea is to get the old dirty oil out of the engine before lay-up.
You did not say whether your engine is raw water cooled or has a heat exchanger. In either case, you have to winterize that part of the system also, but the procedure is different depending on how the engine is cooled. Again, this is easier to do when the boat is in the water.
Some people add a stabilizer to the oil/crank case before lay-up, as well as to the fuel. There's debate about the necessity of doing so but I've never heard that it harms anything.