Hey guys, question for y'all, but first, a little background. I work on a Marine Corps base at the local marina as their mechanic..been around cars all my life, moved to motorcycles, then picked up boats and PWC's. Been keeping their junk running for over a year now, but this has me stumped. We have a 17' Carolina Skiff with a DF40 on it that's got about 260 hours (it's the patrol/safety boat..doesn't see much use) and I've replaced a few things on it as the needs arise...fuel pump, plugs, water pump, etc. Well, now I have oil dripping into the airbox that has me stumped. Running at idle, you can see oil vapor puffing from the breather hose coming from the cylinder head cover. I've taken it off, no junk inside to block oil passages, but on the backside of the cover, there's a plate that stands maybe 1 1/2" off of the cover itself. 3 screws hold it to, but they're RTV'd all to hell and there's no way to take that plate off. Like I said, I moved from cars to boats, so my common sense tells me there should be a diaphragm or check valve in there to allow air to move around, but not oil. But I can't get the plate off to inspect so my best guess is to replace the head cover for $200 and some change and see if that fixes it. I'm not throwing any codes, couldn't tell you what damage it does to the oil level cause I've run it twice in this condition, but taken her back out of the water when I've seen the oil. Anyone have any insight on this? If it were my boat, I'd have more confidence in buying parts, but since I'm spending gov. money, I'd like to not look like a complete moron when trying to explain why new parts didn't work....wives are easier to talk down than a retired Master Guns. 
Thanks.
Thanks.