Onan generator adjustment (run speed/voltage)

[Easybago]

Sent: 9/16/2005

I got that Onan purring tonight, so I checked the output voltage while running and it was 144 volts with no load. I thought this was a bit excessive but figured it may drop considerably once I put it under a load. Well, it did but the drop was not as much as I had hoped it would be. I turned the A/C on and the voltage dropped to 133 volts, which I'm not comfortable operating it at that high of voltage.

I'm not sure which model Onan I have, so here's a pic to help y'all lead me in the right direction.

Thanks a bunch!

Randy

[kd4pbs-1]

Sent: 9/18/2005

Looks like a BFA.

Your speed is probably a little on the high side. These gensets don't have any type of voltage regulator. Basically, you'll want to lower the speed until you read about 125-130 V no load. Then put it full load, and see if you maintain at least 105-110 V. Keep messing around with the governor until you get the correct max voltage. As you can imagine, it's best to be a little off in speed (lower Hz) than higher voltage.

Oh, by the way, I certainly hope you have the air cleaner for that thing!

[firebug911]

Sent: 9/19/2005 10:52 PM

On my Onan  If you set the cycles/ frequency to 60 the voltage takes care of itself... It also depends on what kind of meter you have... True RMS is a bit more accurate.   Rob

[Easybago]

Sent: 9/19/2005

The voltage reading that I'm getting is accurate. Unfortunately, I'm an electrical contractor. My problem is that I haven't figured out how to lower the speed of the generator to lower the voltage. I have four other generators (all different brands and KW ratings) and they each have an adjusting screw to adjust the run speed. I've not found one on the Onan yet.

Thanks!

Randy

[firebug911]

Sent: 9/21/2005

Yours looks similar to mine... The screw is on the gold colored piece on the bottom front of the carb. In your picture it is just above the sparkplug... It has a rod that extends to the left and is hooked to the governor, and is springloaded to the full run pos. ... I have an exploded view and a full parts manual/repair/shop manual if you would like a pic of it.   
Just above and a little left of the sparkplug... It will adjust the speed and the frequency but the voltage is set with the voltage regulator which is inside the generating end of the unit... right side of picture
Rob

[Easybago]

Sent: 11/8/2005

Finally got the genny running well with a voltage I can live with. Thanks for all the help with that.