My BV350 started bogging down. I changed out the spark plug and cap, but that didn't make any difference. I had it fixed at a shop. The cause was a plugged-up fuel filter from debris from a disintegrating air filter. Solution was to change the fuel filter, clean the throttle body, replace the air filter, and clean out the air filter compartment. Lesson learned. Change your air filters on a regular basis to avoid this problem.