My F engine is running way too rich and I can see the carb throttle shaft is loose, letting the crankcase pressure back through the carb at the WOT enrichening port. This port is straight into the crankcase bypassing the reed valves. Have any of you ever reamed and installed a bushing in the Walbro metal body carbs? New carbs are scarce, and expensive. Can't seem to find anything to sub for the OE carb either. Tried blocking off the port completely, runs fine until the throttle goes open, then it leans out and dies. Sure like to get this little motor running smooth and quiet.