Quote Originally Posted by Jim Teasdale View Post
I recently read a forum post suggesting mercruiser engines need repair work every 2,000 hours. Are these repairs a rebuilding of the engine or something else? Does anyone know what the ball park expense of rebuilding a mercruiser engine? Your willingness to share information is very helpful. Thanks in advance.
Hello Jim,

I am, a life long mechanic. I have worked in the diesel, ag, automotive , and marine industries. I am now a professor at UNOH in Ohio. There are a few situations over the years that have been engineering flaws, but more over, it all falls back to a few things. Clean oil, clean air, oil pressure, and temperature. As long as all of these things have been maintained the engine should keep running like a champ.

One of the easiest indicators of engine wear is finding oil in the air breather. This could indicate excessive piston ring blowby. Being over filled with oil could also cause the same problem, or operating in very rough conditions. Your crankcase ventilation system is one thing that gets overlooked often. Engines are designed to pull in filtered air into the crankcase and draw out the crankcase vapor to be re-burnt. it the inlet filtration or PVC system. If either side get blocked though it cannot work. The crankcase can build pressure cause excessive leaks and contaminate the engine oil.

In short, check your breather if it is clean great, if it has oil, check your venting system. and oil level. Another thing you can do is see if you have a lot of vapor coming out of the oil fill or dipstick tube while the engine is running. If you have what seems like a lot of smoky pressure coming out: it is not a desirable condition. ( Note) some injected engines may not run properly with oil cap removed.


Inboard and Outboard, 4 strokes are not much different... 2 strokes are


My 2 cents,, Kent