RE: Engine break in, I'm having trouble.
Yep, you can seal it right up. Get some high-temp RTV (room temperature vulcanizing) silicon gasket material from an auto parts store. I use the red stuff, (because that's what I bought when I was there first), though I hear the black stuff is better. Anyway, I use the red stuff to seal up carb mounts that leak and such. I've also used it to seal around fuel tank stoppers as well.