Originally Posted by Brypoint
These problems showed up after you cleaned the carbs? Could you have possibly bent the float at all? Seems like it may be allowing too much fuel in at the higher rpms (hence the fouled plug) and when your buddy starved it, it began to run better. How's the plug? maybe its not firing properly at high r's and that would cause a rich enviorment too due to not burning all the fuel.
I thought about the float too, but since the last time I messed with the carb and had the bowl off, it has ran 'ok' I was starting to consider ignition, until we started killing the fuel to it. I am really lost now. I think I am going to order all NEW stock jets and start there.