5500 Onan generator runs for hours then stops with over frequency code. Will start again and run for hours then stop again. Any ideas?

SOURCE: 5500 generator stopped producing eletric after

First check with the dealer and see if it is still under warranty. If it is not, make sure nothing is blocking the air flow around where the control modules are located. This could cause the voltage regulator and other electronic parts to overheat. Next check the brushes and make sure they are free of any dust or build up preventing them from making contact.

If everything is OK the next thing I would do is change the voltage regulator.

SOURCE: I have a 6500 lp onan marquis generator in my rv.

ONANS ARE PRETTY QUIRKY AS IT IS NOT CONSUMER FRIENDLY. THE GENSET IS DESIGNED FOR ROUTINE AND SIMPLE MAINTENANCE PERFORMED BY THE OWNER, AFTER THAT, U WILL NEED TO TAKE IT TO THE NEAREST DEALER OR CUMMINS DIESEL REPAIR SHOP.

Kelly

• 3740 Answers
• Posted on Aug 01, 2011

SOURCE: My Onan Emerald Advantage 5500

Hi and welcome to FixYa, I am Kelly

I can probably help you figure out where the wire goes if I had an idea of where this wire originates.

There are 2 wires connected to the side of the fuel pump I think either one of those 2 wires is the one your missing or the


Here is the start sequence for just the starter:

Sequence of Events:

Battery + pos) at PI-6, Battery - (neg) at P1-8.

Operator pushes start button at AI.

B+ from PI-2 to start solenoid

(S terminal).

Solenoid contacts close send B+ to
starter.

This is the ignition:

Sequence of Events:

Operator pushes start button on AI.

Safeties are bypassed.

B+ from P3-3 to ignition coil.

Breaker points open/close path to

ground.

High voltage jumps spark plug gap.
B+ supplied to fuel pump from PI-2.

This is the ignition / running:

Sequence of Events:

I. Engine starts, oil pressure causes

LOPKO to close sending ground

signal to P3-4.

AC from generator B1 -B2 winding

enter board at P1-1 and P1-7.

These two inputs cause the control

to switch from start mode to run
mode.

Starter automatically disengages.

Field flash automatically removed.

Start switch released.

Safeties enabled.

Bl-B2 powers choke heater (Hl).

Fuel Pump power now from P3-6
through R7.

The fuel pump power for run is from P3 pin 6 though resistor R7 to the fuel pump. THIS may be the wire that was damaged. However... a broken wire from the low oil pressure switch (located under the oil filter covered by metal cover) or... no AC output sensed on the control board due to a broken wire to P1-1 or P1-7 it will never switch to the run mode.

Your going to have to do pin to termination point readings one wire at a time. More in next post... (30 minutes or less)

Kelly

SOURCE: onan generator cranks then wines no start i have a onan generator in my motorhome it stop running now when i try to start in it turns over but does not run what should i9 cheack

check oil level in the sump
if the oil level is correct check for a problem oil level sensor circuit
it is there to stop the engine when the oil level reaches critical level