Portable Generator Erratic Engine Speed

Engine speed is directly proportional to the amount of fuel the fuel pump sends to the fuel injector. The amount of fuel the pump can pump is controlled by a metering valve. This metering valve is part of the fuel pump assembly. The throttle moves this metering valve between closed and fully open or any position in between to control engine speed.

When there is a demand for more power such as under heavy load more fuel is needed. The pump gets more fuel because the speed governor makes minor adjustments the metering valve. The governor is a centrifugal wheel that pushes against the throttle to make speed adjustments. The pushing and pulling is all done with two springs rather than physical contact so if the tension is not correct it can't do its job. To check the cause of erratic speed simply hold the levers that the springs are connected too and increase the speed manually. Hold it and see if the engine speed become stable. If it is, then you need to make adjustments to the springs. If the engine will not stabilize, then it is NOT related to the governor operation. You have some other fuel or fuel delivery issue.