# Winterizing mercruiser 470??



## chris rab (Jan 4, 2012)

What is all that needs to be drained on the 470 which is a closed cooling system? Just the heat exchanger?


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## Shortdrift (Apr 5, 2004)

Thats it. You should also fog the cylinders And make sure all lines carring lake water sre drained.


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## BlueMax (Dec 3, 2006)

For the last 7 years or so I drained the heat exchanger of sea/lake water on my 470. The manual indicates other areas to drain but I could either not find them or they were dry. I always forget which of the two drain plugs on the heat exchanger is the sea water so I refer to the manual. I jacked the front of boat as high as it would go to allow all water to flow out of heat exchanger as drain plug is on the transom side of the heat exchanger. Verify you have good coolant in the closed system. Should be if you mixed a 50-50 solution. Make sure you drop the outdrive down to it's lowest position to drain water. Best to leave it down over winter so any hoses/etc. do not get a "set" in them. As Short Drift stated fogging the engine is a good idea. Also tape over your fuel tank vent to avoid absorbing moisture into the 10% alcohol gasoline. I would purchase a manual for your specific model year 470. It will be the best $35 you spend on the boat.


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