A little bit of moisture under Oil filler cap common?
 

Boat has been sitting for about 4 hours since running it hard today. Oil temps were above 200 most of the day. Was checking fluids and such and check the breather hoses and oil filler cap. There was a little bit of moisture under the cap, is this normal after sitting. Checked the breather hoses as well, didn't see any moisture there. Just the cap. I'm fairly confident that while running there is no moisture, but wasn't sure if after it sat for 4 hours or so if some moisture under the cap would be normal??

It's pretty normal. Just burning off the condensation in the oil.



Darrell.

I guess it surprised me a bit when I saw it, figured after a day of running upwards of 220 degrees at times, it would be dry as a bone. Just didn't know what would happen when it starts to cool back down.........

Unless you have a PCV system, not all of the water will be purged.

Some of the water (in the form of vapor) will remain in the engine since there is no positive draft in the crankcase & valve covers. Although blowby does come out of the draft tubes at all times, blowby contains water vapor so the vapor is never really removed.

The PCV system pulls more air through the engine than there is blowby, eliminating condensation. I had this same issue until I installed a PCV system.

FWIW, I doubt the small amount you are seeing is an issue, however.

I do have a Pcv on one side going to the intake. I talked to Eddie at Young Performance about this as well. He says it's normal as well. It was explained to me due to the block being cooled at 160 degrees, the temperature difference will have some condensation. I guess if my breather hoses had moisture like I had before my reversion issues, i'd be more worried. I used to be able to get about half a teaspoon of water out of the breather hoses, not anymore. Just the couple of droplets under the oil cap.