20 Most Recent Onan Cummins 4.0 KY-FA/26100 RV QG 4000 4000K Gasoline Generator Micro Questions & Answers

If this unit dies under load conditions, decrease your load and try it again. If this happens under no-load conditions, check your fuel supply. Start with the filters, then check pressure and flow.

Hello Martin, Your generator might have a low oil pressure shutdown switch. First check the oil level. If oil level is low, fill oil to proper level. If oil level is fine, I would install an auxiliary oil pressure gauge . If oil pressure is normal, I would change the oil sender unit. If oil pressure is low, I would change the oil pump.

Check rotor slip rings for cleanliness, brushes, stator resistance, rotor resistance. Then replace control board if they check out.

Hi John: Sounds like you may have a bad starter. Can you bench test it?

Check the slips rings and brushes, check the stator and rotor windings for continuity and for shorts to ground. Check PCB plug connections. After that you need a new control board

if it stops running after you let your finger off the start switch, check the rotor, rotor brushes slip rings for cleanliness. Check all wiring plugs back to the control board for tightness. The control requires a feedback from the stator, if it doesn't see it, it will shutdown. If all that checks, have someone ohm the stator windings. Then it;s your control board most likely

That sounds like the reed valve sticking or dirty. You will need to take out the reed valve, clean and re-install. Be aware that a small amount of oil is common, also do not over fill the oil. The full mark is hot. Too much oil in the crakcase can build up pressure and keep the reed valve open.

I can provide you with a picture, can you post and email?FYI it is seldom the reed valve, but it can cause it. How old is the unit?

You say Guardian that is Generac???? Then you indicate Onan 4.0KY. If it is a Onan and it stops after you release the button there are a couple of things. 1 st check the brushes, and polish the rotor slip rings, check the resisitance of the rotor, the electrical harness plugs are tight. The control requires a voltage feedback while cranking to engage the PCB run circuits, if all those check out you have a bad control board.

It is a screen on the muffler output, also remove the plug on the bottom of the muffler to remove carbon

Some Onan 4KW do not have auxiliary battery charge windings and rectifier. Are you sure you have one? If not you will need and external charger

Model spec number? be more specific please

Which motor, which generator model and Spec

Did you get this fixed? this is an old post. If not visit www,advanced-power-technologies.com (Cert Cummins Dealers) They can answer your questions.

You may have dirty rotor slip rings, or bad brushes. Field voltage must be maintained. Check those first

Contact www.advanced-power-technologies (Cummins Dealer) with exact model and spec number. Also there are cold weather options, and cold weather models. Many people buy the RS units of the net, only to find they have been stuck with warm weather models, and they don't start. Does it show a code, or a code 45.

What model? Please be more specific.