Hi Sapper,
Possibly the air vent vacuum inlet was knocked out, spun and misaligned or damaged or blocked or vacuum hose was disconnected. This vacuum venturi inlet is located under the chassis. You can simulate this over reving to all PT or Victa 2-Stroke engine by disconnecting the vacuum hose on back cover of the carburetor. I will do videos on this one to demonstrate over reving and governor.
Cheers,
CM
