I just bought this used motor and used 3-4 times and it was running fine. The guy just replaced the fuel pump, plugs, water pump. It ran fine for awhile one day and then after about an hour of sitting I started it and it ran a little off beat. It continued to worsen all through the RPM's. It seems like a power loss that's off and on all through the throttle. I have checked just about everything. It will idle(but rough, off and on) and won't cut off on it's own. The carbs were rebuilt also before I bought it. Any suggestions?
