I just got my second OS 70 FL 4 stroke. Not because I'm cheap, or don't know any better, but because it only weighs 1.1 ounces more than a .46AX. Anyways, it has the typical ABC squeek, only on a 4 stroke, it's more noticable at TDC on a non compressed stroke. I've broken it in on the bench, and I've burned 2 tanks on the ground, and 1 in the air, and still sounds like an old chevy with a stuck lifter. My question is when will the squeek go away? Or will it?