merc 454 mag using oil!!
 

I just bought a 90 powerquest 290 enticer and used it twice before tearing l/u down to repair worn gimbals..etc. Have noticed that the right engine is using too much oil. The left engine doesn't use any, the engines have 750 hrs and boat was well maintained. All stock other than edelbrock intakes. Haven't done compression tests or leak down yet, Any suggestions on common areas to look at for oil consumption? did notice that exhaust bellow and y pipes on this engine is wet inside with oil, the other is dry. It was at full mark and took it out sat and sun, then oil was on add mark, noticed an oil slick in rear of boat when this engine is running. Maybe valve seals. Both engines have the same hrs on them and are in great shape. Looks like the intakes are leaking in the rear a little bit outside the engine, could be sucking it in through the intake runners, but then it would run lean. Any help would be greatly appriciated, maybe someone has seen this on these engines and can point me in the right direction. Thankyou

With 750hrs on them, it could be anything from the rings to valve seals or the oil cooler.

Agree. So many things it could be. With that many hours, I would just pull the motors and go through them. If nothing else, they would benefit from a valve job.

The oil cooler?? its burning oil not leaking it. Its only one engine, they both have 750 hrs on them but the other one is fine, its just the right engine, I plan to perform compression and cylinder leak down tests next summer, maybe i'll get lucky and only need valve seals. the oil cooler won't leak into the exhaust. I have had these kind of boats before and i know the engines don't really have a problem with buring oil unless something is wrong. Maybe pulling in from intake runners. Thanks for input!

wow...just had a brain fart...it could be the oil cooler..completely forget that the water goes out with exhaust!! Thanks for the input!!

Do yall think that 750 is "alot" of hours on a boat. It has been taken care of, that is for sure..

Yes if you can get 750 to 1000 hours on a stock boat motor you are doing good. But if you have one using oil I would pull it before you cause more problems and spend more money fixing all the other stuff that it takes out when it blows. You still have good parts that can be rebuilt. It's always cheaper to rebuild a motor before something gos bad on its own.

And the only reason it lasted 750 is because it was taken care of !!! Now it is time to spend some money. As mentioned it is cheaper to rebuild now than replace everything later. But that is up to you.

well just dropped $2,500 in gimbal ring and transom repairs, gonna use it next summer and monitor the consumption.

750 is a lot of hours. Any hours after that are a bonus.

On a 454 mag, I would expect top end refresh's in the 400-500hr range and full rebuilds in the 800-1000hr range if they are well taken care of.