the o ring in the cap is very important and so is the cap. Try that first to see if your problem goes away. Might want to try a new reservoir bottle as well and they come with a new cap. This the route I would go as it is not that expensive to buy. There is 3 different versions to buy so buy the correct one per your app..

NEXT Possible is the remaner - the rolling torque for putting the upper together was set it up too tight.

post number 11 explains about the reservoir and cap

http://www.offshoreonly.com/forums/d...low-oil-2.html

I'm curious.......Why would the rolling torque being too tight cause foaming? If it's due to the increased heat that would generate, this upper runs stone cold to the touch, as does the lube. I drained it immediately after running it 45 minutes at 3000-3500 RPM and it wasn't even warm.

Replaced the cap.....Problem solved. The reason I was sceptical of it being the cap was because the issue started exactly when the new upper was installed.......Heck of a coincedence.
That's for all the input.

Thanks for all the input.

I have a bravo 1 with the same issue. I'm running Amsoil gear lube and anything over 3000 rpm and it foams up and overflows. Started happening ever since I replaced the gear lube bottle a few years ago. I ordered a new cap so hopefully that fixes it. Tired of my boat smelling like skunky gear lube. I'll report back once I replace the cap. Thanks for the guidance!

Got the new cap installed and ran it hard. No foam! Thanks again for the help.

Man I should do this for a living and charge for it haha

we carry brand new caps and O rings in the tool box for testing purposes as well. It at times is much faster and easier to rule out or rule in by testing simple things like this plus a really fast testing method. The same with brand new IAC s. Another tool for techs to carry in the tool box.

your welcome