3.7L Mercruiser Problems

[pennyboating]

I have a 3.7L mercruiser, It is the 4 cylinder, 165hp, with the closed cooling system using the heat exchanger. I have water mixed in the oil and a slight smell of gas in the oil. I checked the dip stick and it is very cream colored. I have no clue where to begin checking things on the motor in order to fix it. If anyone has any advice then that would be great!! Thank You for your help. PS I just bought the entire motor and outdrive from someone so the only thing I know is that they took it out and he said something went wrong so they just parked it.

 

[renny1]

Re: 3.7L Mercruiser Problems

well theres definately water in the oil my 10 cents says its your head gasket

 

[TilliamWe]

Re: 3.7L Mercruiser Problems

Do a search on here and you'll find out everything you never wanted to know about the 470 (3.7). DonS will be along shortly to post yet again about the seals that fail and allow the coolant into the oil.
Fix it and sell it.

 

[TilliamWe]

Re: 3.7L Mercruiser Problems

It's not necessarily the headgasket. That particular motor has some peculiarities that allow coolant into the oil without it being a headgasket.

 

[bruceb58]

Re: 3.7L Mercruiser Problems

There are many things that can cause water in the oil. The 470 has the added cause which is how the water pump is designed at the end of the camshaft.

 

[Don S]

Re: 3.7L Mercruiser Problems

Do you have water, or antifreeze in the oil.
The 470's are an open deck design, and are really hard on head gaskets. Especially if you have had an overheat. Have you?
Then there is the cam shaft seal under the engine circulation pump that can allow water (antifreeze) into the oil.
With gas in the oil, replace the fuel pump. The seals fail an pumps gas directly into the oil pan.
If you are not sure if you have antifreeze or water in your oil, drain the coolant and pressurize the closed cooling system with a radiator tester. It should hold pressure.