Onan 4000 won't start...again

[Artum_Snowbird]

A month or so ago I posted about my generator not starting. I thought it was the starting solenoid. I did buy a new one, installed it, and it's exactly the same problem still.

The generator clicks, but will not turn over. This is a two year old unit with only 80 hours on it.

So, I took a measurement of the voltage into the starting solenoid. On shore power 14 volts. When I engage the start button, full voltage goes to the new start solenoid. Same clicking sound. Output of the start solenoid is still 2.7 volts.

Somehow, voltage is being sucked down. Flywheel turns easily. I used the 9/16 wrench on the fan, no problem there. No whirring sounds from the starter at all.

I put jumper cables onto the unit ground, and the positive terminal of the start solenoid. No change.

It does not turn over at all.

Any suggestions before I have to pull the unit out and go directly to the starter?

[j-d]

We must never ignore the GROUND! So much focus on Fuses, Switches, Terminals, forgetting the Other Half of the circuit.
Glad it's fixed. Shame "somebody" didn't get it tight.
I used to fix lots of GM/Delco starters. Plenty of them, many parts interchangeable, special tools not needed. I could usually get two or three good starters out of four or five failed ones. Buddy had a parts shop and I could get the easy parts from him. Bearings, Brushes, Solenoid, Drive. Then he opened a rebuild shop and I could get a Armature, or a Field, even a "Nose" to change application.
He offered me this simple test process:
If it won't run, bypass Solenoid.
If it runs then, replace Solenoid
If it doesn't, replace Brushes
If it runs then, see if the Drive kicks to engage position
If it doesn't, clean or replace Solenoid or Drive
With starter running on the floor, hold down with one foot...
Jam end of a 2x4 into the Drive Teeth
If Drive teeth smoke the 2x4 and keeps running, setup is good
If Drive stops and Starter runs, replace Drive
If Starter stops, repair Starter (Armature or Field)

Ammeter's nice, but this pretty much covers it.

[Gjac]

Glad it was something simple even though a lot of work to find and fix.

[ctilsie242]

Nice to see a happy ending to this story. Hope the generator lasts you a good long while.

[Artum_Snowbird]

Oops, sorry. I thought I had updated all my posts. I borrowed a motorcycle jack from a neighbor and supported the unit easily while I undid the bolts. The hardest part was pulling the A/C wires back to the unit from where they went to in 1/2 inch flexible conduit, but with the DW pushing and me pulling we pulled out the wires and left in a pull wire.

Once I got the cover off the only thing wrong was a totally loose positive connection on the starter. I cleaned up all the unit (it only has 80 hours on it) and put it back in by myself then with me pulling and the DW pushing and adding dish soap to the wires, we got it back together again and it ran fine.

I can definitely see the minimum price of $600 for a re and re job alone, it was a pain in the butt, but I am glad I did it myself.

[fischer]

Just remember the world will not work without battery and ground.

[DrewE]

Juzaxadar wrote:
Dumb question, maybe. It's in the back so how do I hit it with a hammer? I'm trying to avoid taking it out if I don't need to considering the time investment everyone is saying is involved.

Assuming it's a typical sort of installation, you can't get at the starter without removing the generator, unfortunately. You need to remove the outer upper case from the base plate, and usually that means dropping the generator since you can't lift the cover off with it installed. (I say "usually" because if I said it was always the case someone would point out that the '93 Craftwood Magnificat motorhome, of which five were built, provided access to the generator from above by swinging the couch seat up out of the way or something similar.)

[Gjac]

I went through this with mine several years back and it drove me crazy for a while. The lesson I learned is just because it sees 12 plus volts that doesn't mean the amps required are getting through. Also I could not turn it over with jumper cables either. After cleaning and tightening all the battery connections I traced the line going from the genset to the battery I noticed the wire inside the crimped copper terminal was green and slightly loose after I clean the wire I soldered the terminal onto the wire and all was well again. I would check carefully your battery connections first and make sure they are clean and tight then wiggle your wires. It might be something simple especially on a newer MH like yours. Good luck.

[Juzaxadar]

Dumb question, maybe. It's in the back so how do I hit it with a hammer? I'm trying to avoid taking it out if I don't need to considering the time investment everyone is saying is involved.

[PaulJ2]

Like others have said--Give it a good rap with a hammer on the starter motor itself, probably a stuck brush inside. Report back with results.

[Juzaxadar]

Is this the sound it's making? I'm trying to debug mine as well. Mine's a 4KY FA that was running perfectly last month when I started it.
https://www.youtube.com/watch?v=AiA-io1aWf4

[drsteve]

Sure sounds like a dead starter motor.

[Artum_Snowbird]

DrewE wrote:

Artum Snowbird wrote:
Used my professional DC ammeter, got 12 volts through the solenoid this time, and about a half amp. Should be 20 amps or perhaps lots more than that I would think.

My Onan 4KY generator starter takes about 90-100A when cranking, very roughly speaking. It's not a constant draw, of course, since the load is rather variable as it spins, but that's a reasonable ballpark estimate. Half an amp is peanuts.

Thanks DrewE. I wonder if I will find a loose connection at the starter once I get it out of there.

[DrewE]

Artum Snowbird wrote:
Used my professional DC ammeter, got 12 volts through the solenoid this time, and about a half amp. Should be 20 amps or perhaps lots more than that I would think.

My Onan 4KY generator starter takes about 90-100A when cranking, very roughly speaking. It's not a constant draw, of course, since the load is rather variable as it spins, but that's a reasonable ballpark estimate. Half an amp is peanuts.

[Artum_Snowbird]

I will try the tapping. Neighbor has a big floor jack with an 8" pad on it so that might be the final solution. Thanks everyone. Will post the final outcome.