I have an old Honda GXV 530 on my riding lawn mower. I recently replaced the carburetor, fuel pump, fuel lines, filter, piston rings, intake and exhaust valves (adjusted to specs). Prior to replacing the parts listed above, it was smoking and would only run on full choke. After replacing the parts and cleaning cylinders and pistons, it will crank easily, doesn't smoke and runs well up to half throttle, but once I pass half throttle it requires full choke. Runs smoothly with full choke, but I would rather not have to run with choke. Any suggestions on what to look for or adjust? I have not looked at or adjusted the governor. This model does not have a fuel/air mixture adjustment that I can find. Thank you for your help!