I have a 1987 wellcraft antigua with a 454 7.4L mercruiser. Raw water cooled. My oil was fine all summer and about 2 months ago I towed a capsized boat to shore this was really hard and my boat was quite weighted in the stern. I checked my oil the next day and it was milky. took 3 changes to get it clean again. Oil stayed fine all summer right up unitl I pulled it out of the water this weekend (with crane onto a craddle). I went to winterize it and again my oil is milky. When it happened the first time I checked my risers and they were fine.

any thoughts on why all of a sudden I have chocolate milk for oil? could the liftign caused water from the exhaust to get into my oil? I am really frustrated i have no clue any help would be great.

Thanks,

My first guess would be exhaust,but you checked that.I doubt that lifting the boat out could cause it either.As for towing the additional strain on the motor...maybe.
Right now I am thinking that as its getting colder you may have a head gasket leaking.Its taking longer for the engine to come up to temp and its leaking then.
You got all winter yank the motor and find out why.

Remember, condensation inside a motor - particularly when it gets colder - is normal. When you run your motor for longer periods of time, the condensation gets cooked off by the heat of the motor running. If you just ran your boat for a brief period of time getting it from the dock to the crane, you might not have cooked everything off.

Before you do anything serious, do a compression and leak down test.

I would also suspect an intake gasket, they rot around the coolant ports and will dump water right into the oil.

all the above also check the exhaust flappers in the y pipe,may be getting some backwash water whyle the boat is sitting.

Also how milky just a trace...or tan or white.

Thanks guys here is some more info:

I have had oily water coming from the crankcase vent hose all summer even when my oil was fine on the dipstick.

right now the oil is looking like chocolate milk or coffee with cream in it, a tan color. not sure if thats a lot or a little. i think its alot of water the level is high on the dipstick. this is why i think something happened to letin a lot of water at one time. The week before there was no sign of water in the oil.

where should i start? Take the risers and intake manifolds off?

thanks again

It is going to be one of these listed. Listed in order of most probable cause.

Bad riser gaskets
Cracked manifold or riser
Bad intake gasket
Bad head gasket
Cracked head
Cracked block

What should i do first? does the fact that it only seems to get water all at once after no water for along time mean anything?

thanks,

Pull the oil cooler and check it for leaks.