Oil on the intakes?????
 

I see a small amount of oil running down to the bottom part of my intake manifolds. This happens on both motors and have seen it before and after total re-builds.
They are 500HP carb motors with the Dart intakes (Merc Blue)
The oil may be coming from the right side center bolts (2) .
Do I need to re-torque? Since both my motors do this and still after a re-build I would hope this is something minor that you guys have seen before. Thanks for the help
Scott

It's the intake manifold and I re-used the stainless socket head cap screws that Merc used. Remember this problem seems to be following me around from before the rebuild and I might add this is a very small amount of fluid may not be oil but I can't imagine what else it could be.

Scott, Is it possible that the oil is from your breather hose(s) which run from the valve covers to your flame arrestor? It is not unusual for a small amount of oil residue to be drawn from the valve covers through these hoses and then drip onto the carb, flame arrestor or intake manifold. Just a thought.

I don't think there are any pressure spots w/in the intake that would cause a visible oil leak. Even a leaky valve cover wouldn't build up pressure to leak on top. I think DrN. is on the right track. as the oil cools it, too, condenses and can "drip" onto things from the breathers. Most marine motors pruduce blow-by. A high flow flame arrestor might allow more of the oil to be consumed by the motor.

It could be wicking up the bolts to the top. That happened to me once. I used a sealant to stop it. The same stuff you would use on a bolt near a water jacket.

This is very common on hot rods. The two center bolts for the intake to the head are NOT blind holes and go out the bottom of the head and into the lifter valley area. If these bolts and threaded holes are not very clean with a little sealer on them oil will work its way up the bolt and puddle in the intake. It is very hard to stop this once it has started. Try some acetone to clean the bolts and the threads, after you replace the bolts with some thread sealer let it dry overnight before use.

That should stop it.

Thanks guys sounds to me like it may be the thread issue. I have checked the breathers and found them and the flame arrester dry. The boats in storage so no big deal for me to clean the threads up and try to re-seal them. If I remember right I used ARP sealer on them,I will switch to the black goop.

Scott