Small Engines (Lawn Mowers, etc.): Mower, open throttle, throttle control

Question
Thanks Marc!

It was a combination of the grommet and the tube not being pushed down as far as possible so the oil was not getting a good seal... Also, upon close inspection of the gas line, it was cracked and broken beyond the point of carrying gas... After replacing this, the mower started up after a few pulls. However, it idled weird and only got enough power when we manually adjusted the throttle... How is the throttle supposed to work? That is, is it pulled by something inside the engine by way of the arm and reset by the governor spring?


Thanks,
CSB

Answer
Here is how the governor works.  The spring opens the throttle and it's tension is controlled by you (with the throttle control).  As the engine revs up, there is a set of centrifugal weights that operates the governor to reduce the engine RPM to the desired level.  This way the spring can hold the throttle wide open when there is more load on the engine and the governor will not act to close the throttle unless the load is reduced or the engine has sufficient power to overcome the load and doesn't require wide open throttle to maintain the desired RPM level.  Check to make sure the governor spring is still intact and connected properly.  If the engine surges this indicates the governor is working correctly but the carb is unable to supply the required amount of fuel to maintain engine RPM.  Hope this helps.