20 Most Recent Watts Onan Portable Generator - 4000 , Model# 5500 Questions & Answers

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Watts Onan... • Answered on Aug 19, 2019

Onan units have a breaker switch on them that has to be in the right position or you get no power. Can't tell you for sure where it is on the 4500 but on the 4000 RV series it is tucked in behind the on board start switch

Watts Onan... • Answered on Mar 30, 2019


It does sound like your fuel pump is having issues, or the relay that controls the pump is the culprit.

If you have one, put a multimeter across the fuel pump wires. Start the generator, you should have 12volts when trying to start, as well as when the generator is running. If you dont, then you are looking at a control relay failure. If you do have the 12volts, wait for the generator to start surging, and monitor the voltage. If it stays at 12, then you are looking at a failed pump.

If you post the Onan Model / Spec / Serial number, I may be able to find a service manual for you.

Watts Onan... • Answered on Feb 25, 2019

Usually what that means is that the genset Configuration is not set correctly you will need to bring it to a factory authorized service center for them to correct this.

Watts Onan... • Answered on Sep 27, 2018

hi check that the voltage regulator is in good working order, check insure the governor is free from dirt and that the retainer light spring is not fouling , and check the volcanizing elements are not shot circuiting or the insulation is braking down

Watts Onan... • Answered on Jan 02, 2018

No, not the filter, you will need to try to prime the carb better then with starting fluid, pour some gasoline down the carb, you may have to do this a few times, but everything will fire back up again once you get the air out of the system

Watts Onan... • Answered on Aug 25, 2017

This might sound dumb ... is the fuel valve turned on?

Watts Onan... • Answered on Aug 25, 2017

This sounds like overheating. These small generators don't have overheating protection, but if a low oil pressure or low oil level is present it may be the reason for stopping.

Check the oil level in the starting conditions and again when it stops. It may become under the "stop" level and after some time the precipitated oil has reached the "start" level. The same may be with oil viscosity and oil pressure.

Try to add some oil or change the oil with bigger viscosity.

Watts Onan... • Answered on Aug 25, 2017

sounds like your coil is done

Watts Onan... • Answered on Aug 25, 2017

this may sound like a smart *** answer but turn on its side and shake it the low oil switch is stuck

Watts Onan... • Answered on Aug 25, 2017

Try to restart to see what happens. However, make sure to have a volt meter to check output voltage. You may be loosing voltage and therefore it shuts down. Check oil pressure switch, rings, brushes. Replace brushes if they are less than 1/2" short and clean rings with emory cloth until copper is noticable.

Watts Onan... • Answered on Aug 25, 2017

First locate the oil pressure switch and see if you can bypass it,then see if it runs. If not check the fuel filter and fuel pump,make sure solonoid for fuel pump is kicking on.

Watts Onan... • Answered on Aug 25, 2017

Remove the air cleaner and inside near the throat of the carb is two bolts holding the carb to the intake remove these. Unhook the fuel line and twist the carb to allow the linkages to remove.

Watts Onan... • Answered on Aug 25, 2017

Our motorhome Onan 5000 Marquis generator will turn over and try to start but fails everytime we test. We have primed, gas and oil are fine and we have new spark plugs. We also changed the gas filter on the generator. Any suggestion? Thanks, Loretta

Watts Onan... • Answered on Jun 07, 2017

http://www.cumminsonan.com/locator The A1 controller is likely suspect.

Watts Onan... • Answered on Apr 04, 2016

sounds like coil

Watts Onan... • Answered on Apr 04, 2016

It is right behind the start switch. There is one bolt that holds your start switch housing down, remove it and the housing. You will see the P1 connector with a lot of wires plugged into the control board

Watts Onan... • Answered on Nov 13, 2015

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