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HELP Water and steam at valve cover

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rossbruno

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I have a 5.7 Mercruiser inboard running fine no water in oil and not overheating. After it warms up I am getting steam out of the valve cover vents. Took off pcv elbows and I can see a small amount of water in there. Any Ideas what is happening?
 
rossbruno said:
I have a 5.7 Mercruiser inboard running fine no water in oil and not overheating. After it warms up I am getting steam out of the valve cover vents. Took off pcv elbows and I can see a small amount of water in there. Any Ideas what is happening?
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No one in Merc land wants to help? The water you see was in the oil, just not enough to turn it milky yet. You could have an oil sample tested. Could just be condensation if you dont run often or long enough to burn it off. Pull the spark plugs with the engine cold look for any sign of water. If so most likely your risers are bad.
 
may not have been in the oil but definitely inside the engine....I'd agree, need more info to narrow this down.

how long was the engine dormant before this scenario unfolds...what was the temperature and humidity variations during the dormant period?
 
I live in Tampa Florida: Humidity 90% 8months a year. The boat was sitting on the lift for over one year with no starts. Gas tank had about a gallon of water in it so I drained tank and had Carb rebuilt. Runs great now. Ill drain the oil today. any other things I should do? will it be safe to run as long as the oil dosen't get milky?

Thanks alot for answering.
 
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tampa = humidity...any time the temp dips and you can see dew on the cars/grass/etc, it can form inside of an engine. Oil change is a prudent step...as long as the oil doesn't show water, you should be fine. I'd be inclined to change the fluid in the gear, too. The last thing would be to get the integrity of the o-ring on the fuel tank's filler cap just to make sure that wasn't the source of the water in that tank.
 
A gallon of water in the gas tank is not normal, even in the tropics over a year's time. Rain water has gotten in, or worse, sea water if it was rough and got in thru the overboard vent. No way is condensation over a year's time in FL going to get you a gallon of water in there. Like MM said, check the o ring at the fill, make sure the vent has a rise in the hose, and check for fumes in the bilge. I've seen foamed in tanks that allowed rain/deck water to invade the tank thru hole or holes.
 
Hi, I'm new here. I rebuilt the top end of my engine of a boat I bought a year ago as a basket case. The thing runs great at an idle and takes the gas really well with a set of ear muffs. When I get her out on the water, I don't have the power that it sounds like it should have at home with the ear muffs on. I replaced the heads (350 GMC) there were cracks on both sides, both risers, carb, complete tune up, and new water pump-both in outdrive and motor. When she starts and warms up a bit there's water coming up threw the hoses from the valve covers to the carb. It's a 1986 mercruiser, 350 engine. Any help would be great or any ideas. the humidity has been bad up here in Northren Pa. lately. She just won't run right, but no misses, no shake, and I haven't pulled any plugs yet.
 
First off, you've posted in the crusader section about a mercruiser problem on an old thread...

How an engine "performs" at idle vs spinning a propeller in the water are two radically different scenarios and really shouldn't be compared.

Assuming you have water vapor coming from the vent pipe, that may not be abnormal...if you actually have liquid water exiting the hose, the engine has a serious issue.

As far as "She just won't run right..." thats pretty wide open and could be rooted in anything...
 
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