ORIGINAL: HimotoRacingUSA

a little leakage is normal on a used engine, only a new engine will have no leakage. After a few tanks that pinch is worn away enough to not be so airtight, i wouldnt worry about that.

Sound like you could have a loose drive cup somewhere in the drive line or maybe the flywheel is loose and slipping. It could be a bad diff gear, make sure the plastic hex's on the rims are not rounded out.

Just a few things to check.