I've had this engine since new, never been crashed.. The problem seemed to slowly occure. It will start fine will idle and accelerate ok just a little slow on acceleration. The low end addjustment is working, it will change the idle. The high end will change the RPM at full throttle but where it runs best is 1/4 turn out. I thought it use to be about 1 turn. Running an OS-F plug 10% wildcat fuel 14/8 prop. Any ideas?