Onan Generator - The Hull Truth

Released · 09-28-2008, 04:57 PM

My older Onan Generator starts and runs fine until I let go the Start button, Then it turns off. All fuses are fine and it is full of oil. It happens on both switches. Any thoughts are appreciated .

Thank you

A1 Outboard · 09-28-2008, 05:46 PM

Not being familiar with your generator, but have seen those same symptoms often, though, on other motors.

On most gasoline engines, the stater solenoid has a post ( I terminal) on it that bypasses the key switch to provide higher voltage to the ignition system. If there is a problem or open circuit in the key switch, the wiring or possibly in your case, the oil pressure switch, then no "juice" is getting to the ignition system except when the starter solenoid is engaged.

If you understand wiring systems and can use a meter, then troubleshoot the system to find out why no voltage is getting to the ignition. I'm sure you can get a manual for your generator very easily.

A1 Outboard · 09-28-2008, 05:53 PM

I forgot to mention that your generator may have a ballast resistor or resistance wire in the* engine wiring harness that lowers the running voltage to the coil. An open circuit or high resistance in the wire or ballast resistor will give the same symptoms as you have described.

cowboy1320 · 09-29-2008, 02:41 PM

I have the same problem. I've replaced the green printed circuit board and the epoxy enclosed voltage regulator ass'y and bench

checked the oil safety switch... NO DICE !! Onan Emerald 1 120 volt I think 1500 watts,,, the trailer is a 1989 model I would

think the ONAN was the same.. What model do you have ? I would like to stay in touch. A-1 makes perfect sense for really old

Onan's , although with my model I think this is all in the printed circuit board. If I'm wrong maybe A-1 will step back in and say so.

I'm very electrically and mechanically inclined. ( hope I got all that spelled right ) Cowboy