My 66cc engine with nt carb has never ran how it should. Its super rich and the needle is as low as it will go. It 4 strokes for about 30 seconds on Full throttle then it starts running better and picks up alot of power anf even pulled me to 39 mph at wot but after you let off the gas it 4 strokes a little and will only go like 25 mph. I lowered the float twice which helped tremendously and ride without the air filter with a clean carb. I also had a head leak which i fixed and sealed and now it seems like it runs even a little worse and now it wont lean out at wot at all so im thinking im gonna have to rejet smaller but any advice?