I recently picked up a well used chipper with a HM-100 engine. It starts up fine but once off choke, it wants to take off and over-rev. I shut the machine down, lubed the governor linkages, and noticed that tension from the governor shaft wants to bring the throttle to the WOT position. When the engine is running the throttle is pegged open just like when the engine is off. I can use my finger to force the throttle back down but it speeds back up as soon as I release. Is there a missing spring or other mechanism that brings the throttle back to the closed position? Is this a sign that the governor is kaput?