onan 4k generator stopped

[dugarug1]

learn alot here every day, so here is my problem.
1995 class-c, 4000 onan gen, 556 hours, serviced regularly, oil is clean and full.
running my ac by the gen, after five minutes it stopped.
the gen will start by either the inside or outside start buttons, runs as long as buttons are pushed, stops when released, my electric meter stays in the red showing no electric power,
suggested it might be a stator.
any ideas greatly appreaciated
Doug

[Hank_MI]

Hank MI wrote:

Chopperbob wrote:
Same thing mine did. It was stator, rotor, and regulator.
$2,300.
Cummings dealer.
Bob

Our stator exploded, tore up the gen guts. For $3000 Cummins installed a new gen. Would have been close to that to rebuild and now we have new gen with warranty.

BTW: They said mice or something built a nest in there and that's what caused the damage. Our insurance, AAA, covers rodent infestation so they paid for the new gen minus deductible and a couple hundred dollars in depreciation.

Doh! Meant to edit post not quote myself.

[Hank_MI]

Chopperbob wrote:
Same thing mine did. It was stator, rotor, and regulator.
$2,300.
Cummings dealer.
Bob

Our stator exploded, tore up the gen guts. For $3000 Cummins installed a new gen. Would have been close to that to rebuild and now we have new gen with warranty.

[quietjake]

thanks for the tips, I'll be checking into it, & will have to write down the model ID. Went out this AM & it cranked right up and ran fine but did cycle up & a little. Thought I had a manual but it's not in the pack with the rest of the manuals, just a little blurb "this is your Onan 4K" thing.

The Onan dealer has enticed me to bring it in for a look.

[Chopperbob]

Same thing mine did. It was stator, rotor, and regulator.
$2,300.
Cummings dealer.
Bob

[wa8yxm]

I will go with fuel or oil level.. Also the brushes could be worn.

The Onan generators are smart.. If anything prevents the generator from generating power it will shut down.

Check your button flash code for an idea of why the GENERATOR thinks it shut down One code is "Cranking speed too low" This can be due to failure of the generator to generate.. The one time I have seen this the owner had to replace the brushes.. (NOTE: I don't fix 'em, I just remember what it requires to fix 'em when others get 'em fixed).

Fuel filter, Air filter and Oil level are all good ideas too. IF it runs at all after you release the button on a cold start these would be my first choices.

[j-d]

Please post the complete Model and Spec. Somebody here can send you a manual and it'll include troubleshooting charts.

I'm with the guys who are saying "not producing voltage" etc. When Cranking (holding in Start), most of its fail-safes are bypassed. Once it's established running, then it starts checking for output, over/voltage, etc. etc. If those checks don't pass, then the Control Module shuts it down.

Spec is important because there are many running changes. For one, the Oil Level Sensor was discontinued at some point in developing the 4KY. Spec tells you that. You don't want to be trying to find the sensor to check it when it might not even be there.

WARNING!!! Over the last couple years, we've noticed several 4KY's failing because of low oil. The oil level really requires attention in these

[Hank_MI]

Anything that keeps the gen from producing AC will cause it to shutdown. Corroded brushes, bad voltage reg, bad control board. Also low oil or faulty oil sensing switch. All the sensing that causes it to shutdown is overridden while holding the start button, once it's released the control board takes over and will shut it down if there is a problem. Tripped AC breaker on the gen may also shut it down. Don't remember if sensing is before or after breaker.

[quietjake]

my 4k Onan has 51 hours, and until now has functioned perfectly.....the rig is 2004 low miles, so it's mostly sat.

Bought RV 6 months ago, and last used rig 3 months ago. Have gone out to start/run generator a few times per month for 5-10 minutes.

This time won't start, sounds like fuel starvation issue, and doesn't really get going,dies when off the switch.

The Onan dealer wants to see it but can't tell even what 'trouble shoot' will cost. "$100-200" maybe....

seems odd it would suddenly go hayware on me....

[ReelTime]

dugarug1, Allow me to add one more possibility and I know you do not need one more thing that can cause that specific problem.
I have a 1997 four winds with a Onan Emerald Plus 4kw gasoline generator. It just started all by itself to only run when I held the Start side of the switch down(the switch on the generator itself, or the remote switch). If I would let up on the switch the Generator would die immediately. To shorten the story I found that the rubber cover over the Start/Stop switch (On the generator itself)was slightly deformed and would immediately move the switch back to the Stop position just enough to Stop the generator and it was holding it in the Stop position when the remote switch was used. I have a remote start as do many of the Onan generators. One thing I did note after the fact was when the issue started There is a red light in the remote switch and if it did not come on when the generator started the generator would stop immediately when I released the switch. Now the generator starts, the red light comes on and the generator continues to run. Some day I will get another cover for the switch on the generator.:)

[ksg5000]

Get the manual - step by step instructions for diagnosing. Common problem are low oil, bad oil sensor, or problem associated with creating AC (brushes, slip ring, stator)

[MEXICOWANDERER]

Onan uses a LATCHING RELAY that keeps power going to the fuel pump and ignition. This system is BYPASSED when the starter is spinning. A bad low oil switch or other safety SWITCH FAULT can cause these symptoms, a bad latching relay or connectors. You need to troubleshoot.

[64thunderbolt]

could be a gen issue. The manual says slip rings, brushes a possibility. I'd take it to cummins

[Chopperbob]

Mine runs fine as long as the start
Button is held in. Don't think carb.
Anything else scares me.
Could it be a loose connection?

[64thunderbolt]

Mine would start but die when the start button was released. Carb was varnished and when the choke would pull the throttle all the way open it would stick, over rev and shut itself off due to high rpm & voltage. Cummins diagnosed it, replaced carb $433 out the door. Very pleased with their service. Only charged me 1 hr labor for diag & R&R. Those little carbs are pricey. $285.00. Good luck. I should have done a better job. This thing sat for 4 yrs prior to me buying it. Now it's Seafoam every fill along with staybil.

They said it was scheduled with the tech @ 2pm and I picked it up @ 3. Can't complain about that. This was @ Cummins Rocky Mtn in Phoenix.