I have redone most electrical components and fuel of this kohler K341. new spark plug, coil, starter, battery, rectifier, Carb, rewired, but i have not done points. it starts up great idols fine. when I turn the throttle up it rises up to a certain RPM then starts to seize and puff black smoke and the throttle on the the carburetor jumps. Someone had told me it is backfiring and said i need to adjust the my air to fuel ratio. started messing with the governing arm and spring and thought it was helping but hasn't fixed it. any suggestions?