Governor Problems on Tecumseh Engines
Tecumseh engines are built for use in lawnmowers and snowblowers. Common problems that affect the governor on a Tecumseh engine are that the engine runs either too fast or too slow or that the engine surges or hunts.
Some repairs should be left to professionals, but diagnosing the problem with the governor is an easy process for most do-it-yourselfers.
The governor shaft on a Tecumseh engine should face the same direction as the governor arm to open the throttle. Adjust the governor by loosening the screw on the bottom of the governor arm. Push the governor arm until the throttle is wide open. Turn the bottom clip that is connected to the governor shaft counterclockwise to set the governor shaft on top of the governor spool. Replace the screw on the bottom of the governor arm. If the governor utilises air vanes, then make sure they remain clear of debris to ensure that the proper amount of air flows through the engine
Linkage and Spring
Check the linkage and spring of the governor to ensure that they operate freely and are not stretched or damaged. Check that all free play is removed from between the carburettor and spindle of the governor's static adjustment. You can check this when you move the air throttle to full open from idle to see how the governor shaft moves. If the governor shaft moves clockwise, then loosen the clamp screw and turn the shaft clockwise. Replace the clamp screw and check the engine to ensure that the air throttle moves freely from idle to full open.
With the engine at idle, move the governor lever to open the throttle and push the governor arm back toward idle. Remove the governor spring. If the engine continues to overspeed or has no push toward idle, then the damage may be in motor, static adjustment or other internal parts. In this situation, take the engine to a professional for repairs.
If the governor surges up and down, then the problem may be a plugged carburettor, a plugged idle circuit or a worn linkage. If you check these components and see that they work properly, then the set of the governor may be too sensitive. This means that it reacts too quickly and overcompensates for the speed. Move the spring to a hole in the governor arm that is farther from the shaft to decrease sensitivity.