onan 4000 gen dies

[to_old]

I'm I the only one with trouble keeping 4000 onan running?
at wits end! Things I have replaced
1- fuel filter

2- fuel pump

3- carburetor

4- replaced gas cap on motor home (Thinking it might not be venting )

gen will run 20 to 30 min and the just stop ,runs perfect until it just stops
.Has anyone fixed theirs and if so what did you find wrong. Only code it will show is code 3 it will not show second code

[Suburban52]

Hi, I replaced fuel pump and filter on my 1997 Jamboree Onan 4K for stalling when below 3/4 full. Then replaced fuel pick up line from gen to fuel tank, now starts and runs until tank is below 3/4 empty. The fuel line would lose suction after running for a short while.

[j-d]

BStill wrote:
OK, so my genset is 1991 vintage Onan 4BGE Emerald Plus.

A real machine, quality piece of equipment. Well worth maintaining!

[BStill]

OK, so my genset is 1991 vintage Onan 4BGE Emerald Plus. I had a similar issue and tried replacing a few parts but that method could get expensive quick. I took it out and took it to Cummins local repair facility. Turned out my issue was the generator's voltage regulator failing after it ran for a few minutes (less than 30 minutes). The part alone was nearly $300 in 2008 so probably more now. Total bill with labor was just over double that amount. Good news is no more issues and they could do the repair without replacing parts that did not need replaced.

I did a fair amount of research and did not get anything that would have led me to this part as the issue?!

[bobndot]

I have no idea what I'm doing regarding the mechanics of the Onan. Sad to say, I carry a backup unit. A Honda 2000.
It won't run the 13,500 A/C unless I pair or install a hard start capacitor, but it will run fans and charge me back up, that's what I need.
sometimes I think I should be dinghy towing a second MH instead of a car.

[Kennyg]

Kennyg wrote:
had the same problem and I did the same first three items you mentioned. At the time the Cummins Tech indicated that if those items did not resolve problem, then the next item to look at was the PC control board which of course controls the operation of the fuel pump.
Those first three items cost me approx. $600 including labor. For your info the control board is approx. $348 plus labor.
Wish you luck.

Food for thought
Ran the generator for the air conditioner as I drove this weekend to ND. ran both the genny and the ford air at the same time. Big mistake. After approx. an hour battery trouble light started to glow. READ the manual and it specifically states that not to run both at same time. Turned off the genny controlled and had no further problems.

[77rollalong]

I picked up one of these, and a few of the wires off the ford, you can find these on the 4 cyl and the 8 cyl cars the 6cyl are similar wires going in are a bit different though but can still be used as the first pin is 12v and the next 3 are the feed to each coil. you have to use the ford ign wires as the towers are different but it only cost me a few $ for everything I needed.

[j-d]

77rollalong wrote:
...a friends onan coil was failing and I used a coil pac off a 4 cyl ford car I picked up from a wrecker, and used only 1/2 of the pac...

Friends, ^^^^ is the Wicked Smart Tip of The Month! Twin cyl ONANs.

Can get a car pack any day of the week closer and cheaper than ONAN.

Doggone! KNEW I should've kept that bad Subaru pack!

Thanks!!!

[77rollalong]

if your onan is loosing spark, does it have electronic ign or points?, would be either the condenser, of faulty coil that is failing when warm. a friends onan coil was failing and I used a coil pac off a 4 cly ford car I picked up from a wreaker, and used only 1/2 of the pac

[gmctoyman]

Wish SOMEONE would come out with a 4KW generator, that fits the space, to replace the Onan POS !

[maillemaker]

I've been fighting my Onan 4BGE spec G generator with the same problem. Runs for about 15 minutes then dies. I have hooked up a spark light tester and I can tell it is dropping spark.

I sent my Flight Systems voltage regulator and control board back to Flight Systems for testing. They were OK, but said VR was borderline. They gave me a good deal on one so I bought a Slip Stick slip ring cleaner and VR for $209. Would have been $70+ shipping for testing anyway.

I have recently replaced a faulty ICM with a used one; It could still be suspect. I tested my coil primary and secondary coils and they were within spec for resistance.

This weekend I'm going to clean the slip rings (currently measuring 80 ohms - should clean if higher than 30) and then install the new VR and the old board and see if it runs. If not, I will replace the ICM.

I already replaced my fuel pump, though I am pretty sure the one I replaced was fine.

Fuel tank is full.

There are 5 electrical components on my genset. Coil, ICM, VR, CB, Fuel Pump.

All are fairly easy to replace yourself. My fuel pump has a bolt that is very hard to get to when the genset is in the RV as the entire genset sits in a heavy steel "tray". The lip of the tray makes it impossible to access the bolt. I solved this by using a small hole saw to cut a hole in the lip which provides access to the bolt with a socket.

The trick with removing the ICM is to remove the two screws holding the bracket in place (do not drop them down into the genset!), and then you have to manually turn the engine until you find the one, single short fan blade and have it line up with the ICM slot. Then, and only then, can you remove the ICM. My genset uses a 3/8" hex bit on the gen head side of the generator to crank it over. Make sure you disconnect spark plugs first so engine can't fire and run and hurt you. It's easier to turn the engine if you take the plugs themselves out.

VR and CB are behind the front panel and are super easy to get at.

Coil is on the back top and a little harder to get to but not impossible on my RV with a hinged swing-down genset mounting.

Coil, about $100
ICM, about $100
VR, about $200
CB, about $200

Steve

[Stim]

Glad you got it going.
Just another sometimes overlooked item that might help someone else-
fuel tank needs to be at least 1/4 full.
A safety feature to keep from running out of gas when parked.

[OFDPOS]

There is a few You tube videos about exactly what you were describing . Runs fine for about 20 minutes then dies.
The videos were saying the dipstick on the 4K gen is off. Too much oil , they go into detail about taking a turkey baster and sucking out a few oz's.

Symptoms : Runs fine for 20 minutes shuts down , will not restart . Let it sit for 20-30 minutes fires right back up only to die again after 15-20 minutes run time.

Alot of people commented saying that fixed the dying problems.
Thought what the heck , I tried it , nope still did the same thing.

Wound up replacing the fuel pump and fuel filter.

With no instructions and being in a tight place , took me an hour and a half to do it, well put the module back in tightened it down to realize I didn't fully tighten down the fuel pump retaining screw/bolt and let a wire harness drop underneath the module, so basically did it twice having to remove the module housing plate to get access to the loose screw/bolt and reroute wire harness.

Now that I know how to do it , could do it again in a half hour or less.

I paid right at $100. for the fuel pump, fuel filter and some fuel line.
RV place wanted $250 to replace the pump.

Changed the oil and put at proper level .
Ran it for 5 minutes, turned the A/C on and let run for 30 minutes .
Turned A/C off let run another 5-10 minutes ran perfect.
Have done this a couple times now, so far so good...

[azrving]

Thanks for updating. It helps everyone

[to_old]

Ok I fixed it ! replaced the fuel pump again.....
seems onan has a problem with fuel pumps? Thankful I purchased it
Local and not online .Called the onan dealer and told him my
problem he replaced the pump for me and that did the trick.
So I guess I bought a carb when mine was just fine, Thanks for
all the help guys !