Author Topic: Onan 4.OBGE sending 64v to fuel pump?  (Read 57 times)

0 Members and 1 Guest are viewing this topic.

Offline Russ59

  • Test Driver
  • *
  • Posts: 3
  • Member since: 2021
  • I own: a Motor Home
  • Year: 1988
  • Make: Winnebago
  • Model: Chiefton 22
  • Chassis: Chevy
  • Engine: 454
Onan 4.OBGE sending 64v to fuel pump?
« on: June 07, 2021, 01:23 PM »
I am having the strangest problem?
My 1987 Chieftain Onan 4.OBGE is sending 64 volts to the fuel pump.

After rebuilding carb and replacing the fuel pump, (It did not run when I purchased this "everything worked when I parked it" classic", it still would not fire off. When I checked the voltage to pump it was wonky.  I Disconnected supply and went straight to battery and it runs and produces 120 volts like a charm under load or no load. The circuit board and rectifier are working just fine. It starts and runs great at generator and remotely. When it is running my Fluke VOM shows 64 volts dc or 40v AC to the wire that should connect to the fuel pump.
Looking at the schematic for the gen. and the 332-2985 circuit board, the fuel pump is supposed to be connected to the coil + wire. I did not drop the Onan all the way out to see if in fact that is the case.
All wiring seams to be factory, and doesn't look like it has been "customized".

Anyone have any thoughts?

Thanks in advance.


Offline Eyez Open

  • New Poster
  • **
  • Posts: 46
  • Member since: 2020
  • I own: a Motor Home
  • Year: 83
  • Make: Holiday Rambler
  • Model: Imperial 33
  • Chassis: P30
  • Engine: 454
Re: Onan 4.OBGE sending 64v to fuel pump?
« Reply #1 on: June 12, 2021, 05:21 PM »
Below is a link to a forum dedicated strictly to Onan, it is worth becoming a member. You will learn more than you might expect to, those guys take then gen sets seriously, and keep each other in check from time to time.