K&B 7.5 help
Don,
It sounds like you could be feeling the interference fit that an abc engine has when the piston is at tdc. If so, that's perfectly normal. You wouldn't want it any looser, because as the engine warms up, it the fit gets a little less tight and the engine develops its maximum power. I agree with couch-pilot; the K&B 9100 is a great little engine.
b/r,
DFF