quick tip for some easy power gains: where the governor spring attaches to the governor arm there are multiple sets of holes, move the spring up to the top one for some increased rpms. Also some Tecumseh 4 and 5hp carbs in stock form only open 3/4 of the way, grind at the spot the armature hits until it can fully open (with the carb off the motor looking at the throttle plate to determine this) and instantly get more torque. got to love free power!