I think your problem is the governor ajustment.
Tecumseh 4 cycle engines are equipped with mechanical type governors. The governor’s function is to maintain a
constant R.P.M. setting when engine loads are added or taken away. Mechanical type governors are driven off the
engine’s camshaft gear. Changes in engine R.P.M. cause the governor to move the solid link that is connected from
the governor lever to the throttle in the carburetor. The throttle is opened when the engine R.P.M. drops and closes as
the engine load is removed.
As the speed of the engine increases, the governor
weights (on the governor gear) move outward by
centrifugal force. The shape of the governor weights force
the governor spool to lift. The governor rod maintains
contact with the governor spool due to the governor spring
tension. As the spool rises, the governor rod rotates,
causing the attached outer governor lever to pull the solid
link and close the throttle opening. When the engine
speed decreases, the lower centrifugal force allows the
governor weights to be pulled in by the governor spring.
As the spool lowers, the governor rod rotates and the
solid link pushes the throttle to a more open position.
ENGINE SURGING
1. Try to stabilize the engine R.P.M. by holding steady the solid link between the governor arm and the carburetor
throttle, using a pliers or fingers.
2. If the engine R.P.M. stabilizes, the governor or governor adjustment should be checked. See "Service" governor
adjustment procedure in this chapter. If the engine R.P.M. does not stabilize, the engine will require additional
checks, see Chapter 9 under "Troubleshooting".
3. If the problem persists after the governor adjustment, check the engine R.P.M. found on microfiche card # 30. The
R.P.M. settings are critical. If the R.P.M. setting for high and low speed are within specification and a slight surge
is experienced, increasing the engine idle R.P.M. setting slightly may eliminate this condition.
4. Check the governor shaft or linkages for binding, wear, or improper hookup. Check the governor spring for adequate
tension. Repair or replace as necessary.
