Cummins/Onan RV QC 4000 generator, 2016 Leprechaun mounted

[MrNorty]

I have the above generator with 570 hours on it, ran great till recently. Now coughing and stalling a lot. Will start readily but power not reliable for my RV purposes. Replaced the fuel filter, air filter, plug and oil. Ran great for about 2 hours, now coughing again. Any suggestions for me? Carburetor, fuel line? Thanks!

 

[Larry N.]

Since it ran fine for a couple of hours, I'd look at a fresh fuel filter- there may have been some gunk in the tank/line that was more than the old filter could handle. Of course a slight leak in the fuel line letting in air might be something to check, too.

 

[DonTom]

I have the above generator with 570 hours on it, ran great till recently. Now coughing and stalling a lot. Will start readily but power not reliable for my RV purposes. Replaced the fuel filter, air filter, plug and oil. Ran great for about 2 hours, now coughing again. Any suggestions for me? Carburetor, fuel line? Thanks!

Any error codes on the genny?

-Don- Reno, NV

 

[Gary RV_Wizard]

Sure sounds like some sort of gunk is getting past the filters, most likely the fuel filter. Changing filter again may be enough, but it could be that whatever the gunk is, it is passing thru the filter, i.e. smaller than what the filter grabs but big enough to choke the carb in some way. One way to test that theory is to disconnect the fuel line at the filter and instead connect it to a fresh fuel source, e.g. stick the hose into a gallon can of fresh gas. If the gen runs for 2+ hours without faltering, you can be pretty sure it's gunky fuel in the RV tank or the line coming from it. But if you still have the same problem, it's almost surely in the carb.

 

[Lou Schneider]

Maybe the carbon canister on the main engine's emission system is getting plugged up. It's supposed to let the tank breathe while the main engine sucks up gas fumes into it's intake manifold. If it's restricted it may be creating a partial vacuum in the tank while the generator is running but the main engine isn't.

Try removing the gas cap while the generator is running and see if the problem goes away. Don't leave it off while driving though, as this will generate a Check Engine error code.

 

[MrNorty]

Since it ran fine for a couple of hours, I'd look at a fresh fuel filter- there may have been some gunk in the tank/line that was more than the old filter could handle. Of course a slight leak in the fuel line letting in air might be something to check, too.

Checked out all your suggestions, replaced the fuel and air filters, new OEM sparkplug properly gapped. Purred like a kitten for 10 minutes then died suddenly. Just. Dead. Now replacing the carburetor.

 

[Gary RV_Wizard]

Checked out all your suggestions, replaced the fuel and air filters, new OEM sparkplug properly gapped. Purred like a kitten for 10 minutes then died suddenly. Just. Dead. Now replacing the carburetor.

Again, what was the shutdown code?

 

[MrNorty]

Since it ran fine for a couple of hours, I'd look at a fresh fuel filter- there may have been some gunk in the tank/line that was more than the old filter could handle. Of course a slight leak in the fuel line letting in air might be something to check, too.

Checked out all your suggestions, replaced the fuel and air filters, new OEM sparkplug properly gapped. Purred like a kitten for 10 minutes then died suddenly. Just. Dead. Now replacing the carburetor.

Again, what was the shutdown code?

Where to find shutdown code?

 

[DonTom]

Where to find shutdown code?

In message number three I gave the instructions.

Click here.

"How to Read Onan Generator Fault Codes (Cummins Blink Code)"

You need to take the cover off the genny and find the switch which has a red light on it.

" They use a blink and pause design to make their numbered codes clear and not confusing. For example, if the light blinks 5 times then pauses, then blinks 1 more time, that signifies Fault Code 51."

-Don- Redcrest, CA

 

[ferfer]

The fault codes are blinking sequence located on the primer button. Press the primer button quickly three times within five seconds. The light above the button will blink in a series, with the first number being the first series of blinks and the second number being the second series of blinks. For example, if it blinks three times at first then six times during the second, your fault code will be 36.

Edit Did not see Don's post.