Oil in intake

Pulled the carb off and having it gone through by Chucks. I looked in the intake and the lower plane(I think thats what it is) has oil accumulated on it. Not a lot, but enough to make me scratch my head as to why it is there. Previous owner had little filters on the valve cover vents and I hooked it up like stock to the air filter can (its what it had and I didnt want to spend $250 on a stock flame arrestor). Is this just accumulation from the valve cover vents?

Might want to do a leakdown test on the engine. If the rings are leaking, crankcase pressure could carry some oil into the flame arrestor, which of course dumps it in the carb.

obnoxious001 said:

Might want to do a leakdown test on the engine. If the rings are leaking, crankcase pressure could carry some oil into the flame arrestor, which of course dumps it in the carb.

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I had a leak down and compression test done on it when I bought it. Ill post the results when I get home. Motor has close to 800hrs on Mercruiser 454.

WaterMike said:

I had a leak down and compression test done on it when I bought it. Ill post the results when I get home. Motor has close to 800hrs on Mercruiser 454.

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That's a lot of hours on a boat engine, it would not surprise me if there was some excess crankcase pressure.

This was done at about 770hrs when I bought the boat

5 slugs at 20 percent or higher.

What oil are you running weight Wise?

OK,, so you are saying you have another 30 hours on it since purchase, and you can bet the leak numbers are not getting better or fixing themselves. A good leakdown will also tell you if it's leaking past the valves or rings, but as I stated above leaking past rings will put excess pressure in crankcase and push oil around, through breathers and even past gaskets and seals.

It's not uncommon to see oil in the intake since they have two wide open breather hoses going directly to the flame arrestor.

obnoxious001 said:

OK,, so you are saying you have another 30 hours on it since purchase, and you can bet the leak numbers are not getting better or fixing themselves. A good leakdown will also tell you if it's leaking past the valves or rings, but as I stated above leaking past rings will put excess pressure in crankcase and push oil around, through breathers and even past gaskets and seals.

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BDMar said:

It's not uncommon to see oil in the intake since they have two wide open breather hoses going directly to the flame arrestor.

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I appreciate the feed back guys. Well, it doesn't seem like it is really a concern other than the motor is getting tired. I was planning on getting 2 maybe 3 seasons out of it before considering a rebuild or repower. It is by no means a power boat, just a fun cruiser. I have read that people have gotten 1500 hours out of their stock 454s, so I figure 1000 hours out of mine would not be a huge chore. If she lets go it will either be a 502 Mag or stroked 488 (what ever .030 over is), which ever is more cost effective.

seems like it would be cost effective to not grenade your current motor and just freshen it up come winter?

stokerwhore said:

seems like it would be cost effective to not grenade your current motor and just freshen it up come winter?

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That is always an option, but what fun is that? I can come up with the money at any time, if I am going to go through the hassle and labor to refresh the motor I would like to buy the right parts and be around 450-500HP. Stock this boat will only do 40mph, she is heavy. Do it right, do it once. The boat is the perfect size for me right now anyways.

What kind (brand) boat is it ?

AzGeo said:

What kind (brand) boat is it ?

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23 Essex Monarch