Re: Onan MDKAL Generator Fuel Solenoid SM2000


 

Mike,

Is it possible that you are talking about the Onan Governor, Actuator (new part #306−5006−01 old#151-0779-01), which increases rpm under load and shuts off when you press stop?

If you are, it is possible that the governor is bad, or the control board is bad.

I am not sure how to test other than to attempt to check voltage changes when pressing start or stop. If there are voltage changes the control board (PCB) is probably OK. There may be a fuse on the control board or in-line with the governor if you get no voltage. You should also see if the gov actuator opens up more fuel when load is added...if not, there is a problem with the actuator or PCB. The purpose of the Gov. Actuator is to maintain constant RPM, regardless of the load. This maintains a constant 50htz frequency.

I carried a spare but never had to use it.

Bill
CW Bill Rouse Amel Owners Yacht School
Address: 720 Winnie, Galveston Island, Texas 77550 
View My Training Calendar


On Mon, Sep 14, 2020 at 10:29 AM Mike Ondra via groups.io <mdondra=verizon.net@groups.io> wrote:

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.

Thanks

Mike Ondra

Aletes SM#240 Rock Hall, MD

 

 

 

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