Onan MDKAL Generator Fuel Solenoid SM2000

Mike Ondra

Hello fellow Amelians,

Having an issue with the genset on SM2000.

After no use for 3 months, it would crank but not start. After 8 sec preheat, pressing START, engine cranks fine, but no ignition. Visual check confirms that the fuel shutoff solenoid is not moving to open position when START is engaged. When manually pushing the solenoid to open valve, starts fine. The valve remained open after release and ran fine for several hours. Normal shutdown. Then, to test, did the same procedure. Would not start until manual push on solenoid, but now does not stay in the open position.

This generator has only the cutoff switches for temperature and oil pressure, no gauges.

Perhaps someone has a quick explanation for the above from experience.


In the meantime, I am trying to figure out the control diagram to assist in troubleshooting. Here’s my logic so far.

The Start/Stop toggle switch functionally cuts off the fuel when pressed to the STOP position. In the START position it must energize the SOLENOID to open the fuel valve. The toggle then “defaults” to a neutral position in the RUN mode, so the SOLENOID must remain energized, but not through the switch or it would be continually energize even when off.

Furthermore, to protect the running engine, a fault in either oil pressure or engine temperature must de-energize the SOLENOID to cut off fuel. The pressure and temperature “senders” lead to a “2 pole double throw” switch which I presume has the capacity to de-energize the fuel cutoff solenoid when the “sender information” does not meet spec.

What I haven’t been able to ferret out is if there is an interface between the START function and the safety cutoff function.

Pressing the START should power the solenoid. Does the safety part of the system need to be “happy” during the start, or is it completely independent and takes over powering the solenoid only AFTER the engine starts?

Will continue the research, but would appreciate insight from other and  would like to know if my assumptions above may be heading me in the wrong direction.


Mike Ondra

Aletes SM#240 Rock Hall, MD




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