Water in Crankcase on 43

"Hey fellas. I'm new to th

"Hey fellas. I'm new to this site and posting so if I break a rule or two, it was not intentional. I,m looking at buying my first inboard which happens to be 4.3 Mercruiser. I know the gentleman who owns the boat and has had it since new ('88). Anyway, the crankcase was getting water in the oil (cream colored oil)last year so he had the head and intake gaskets done last year. The engine only has less than 900 hours on it. I don't know a lot about marine inboards but can make my way around a chevy small block pretty well. Other than a cracked block or cylinder head, is there anything else on a marine engine that could cause this problem. Exhasust manifolds?? Where to I begin to troubleshoot. Thanx for your help. Al"

"Don't bother looking at t

"Don't bother looking at the engine until you determine that the transom, engine mounts, floor stringers and floor are not wet or rotting. If you find moisture in the wood; RUN like the wind.

That said, exhaust mans. are a good start but pull the plugs 1st and look for evidence of water intrusion. If you find water then pull the exhaust mans., etc. If they are tested good then check the exhaust shutters (flappers) at the top end of the "Y" pipe.

If you don't find any water then I would suspect the gaskets or an internal head or block crack."

"Hi Guy,

Thanx for the tips

"Hi Guy,

Thanx for the tips. The boat is an aluminum boat (Crestliner) so I don't forsee a problem with rotting wood, (other than maybe the transom.)I brought the boat home yesterday for further evaluation and found more surprises. The watery oil had been left in the crankcase all winter. I immediateley drained it for now and replenished it with fresh oil. What are the chances of corrosion on the bottom end? I figure there was about 5% water content (estimate on my part), or would there be enough oil to prevent corrosion. Secondly, the engine was not drained of it's water contents. Boat was stored indoors in a non heated garage (I live in Ontario Canada). Block did have signs of antifreeze or alcohol in it as I could feel it on my fingers and smell it. No signs in the exhaust manifolds though. Is it possible that the heads and intake need to be retorqued since they were replaced last year? I'll have to check the spark plugs and flapper valve over the next few days. Thx, Al"

"Oil floats so water was on th

"Oil floats so water was on the bottom of oil pan. If the engine oil was not creamy, that small amount of water COULD HAVE been a result of condensation from a cold engine caused by an open T'stat. Corrosion is always a possibility in any engine. Pull the plugs and look for water in the cylinders. If you find it then RUN from the sale or offer him $4,500 less; the price of a new engine."

"Ayuh,.....

It sure Sounds

"Ayuh,.....

It sure Sounds like you need a New Motor....."

"If the engine was run any len

"If the engine was run any length of time with even 5% water in the oil, it is likely the bearings and crank are shot. If the water ran into the oil over the winter from leaky manifolds or whatever, then the bearings are likely OK, and the block should be good, assuming it has not been frozen.

I can't imagine anyone not draining the block of a boat that is to be stored in an unheated garage in Ontario. Especially someone who has owned a boat for 20 years. Frozen blocks happen frequently to new boat owners who forget to winterize, or do not read their owners manual. You should ask the owner exactly how it was winterized.

900 hours is getting up there for a marine gas engine. It is no spring chicken.

Rod"