Woodalls Open Roads Forum: Onan generator issue - goes WOT then stalls under A/C load
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 > Onan generator issue - goes WOT then stalls under A/C load

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dan_hardison

Delaware, OH

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Posted: 08/10/09 06:49pm Link  |  Print  |  Notify Moderator

I have a Onan BGE-4kw (spec J) generator in my Four Winds Class C. The generator starts and runs great, even under moderate load. The problem is when I turn on the A/C, the generator goes wide open and stalls. If I have someone manually keep the throttle from moving to wide open, it takes the load, never misses a beat and runs great.

The generator has had a recent tune up with a new oil/filter, fuel filter, air filter, fuel pump and spark plugs. The carb has been removed and was EXCEPTIONALLY clean, but a can of carb cleaner has also been run through the engine as well as a can of Seafoam. We've also adjusted the governor linkage (plastic ball/socket end of the throttle linkage) as per the service manual, but still no luck.

Any thoughts? I'm thinking maybe points or governor spring?

Thanks,
Dan

gunny357

North Carolina

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Posted: 08/10/09 07:14pm Link  |  Print  |  Notify Moderator

Sounds like it is running lean and can't take a full load.

A fresh set of point (if not electroninc ignition) would be the first thing I'd do.

dan_hardison

Delaware, OH

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Posted: 08/10/09 07:23pm Link  |  Print  |  Notify Moderator

gunny357 wrote:

Sounds like it is running lean and can't take a full load.

A fresh set of point (if not electroninc ignition) would be the first thing I'd do.
Thanks for the reply. Lean was my first thought as well, but I can manually rev the generator to wide open throttle and it takes the fuel with no problem (both with and without load).

I have a set of points on order (wish it was electronic).

Thanks,
Dan

Generator Jim

Conway, SC

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Posted: 08/11/09 02:24pm Link  |  Print  |  Notify Moderator

Dan
I don't think you have points.

ONAN started using electronic ignition with the spec G model. Your spec J should have an electronic module in between the engine and the generator at the top of the unit. Underneath the module is a plastic ring around the crankshaft with two arms that have magnets on them.
1. The module could have a bad ground. Place a double star washer under the back cap screw holding the module to the flywheel adapter.
2. The module could be bad. Test using procedure from service manual.
3. The trigger ring could be broken/shifted. Remove module and inspect using flashlight and rotate slowly using 3/8" Allen wrench in rotor bolt.
4. Coil could be going bad. Test using procedure in service manual.

JimL

* This post was edited 08/11/09 06:34pm by Generator Jim *


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dan_hardison

Delaware, OH

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Posted: 08/11/09 06:22pm Link  |  Print  |  Notify Moderator

Generator Jim wrote:

Don
I don't think you have points.....
JimL

Thanks Jim, I was just about to click the 'place order' button for a set of point and condensor. So would a dying or out of adjustment electronic ignition module somehow force the carb to go wide open under load? Maybe something wrong out of adjustment with the governor or carb?

Thanks,
Dan

Generator Jim

Conway, SC

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Posted: 08/11/09 06:28pm Link  |  Print  |  Notify Moderator

A slight possibility of the trigger ring misalignment doing this.

I'd look at the float level before diving into the electronic stuff.

Secondary possibility is a split manifold. They are two piece with locating pins and silicone "glue". The glue sometimes gets brittle and falls out leaving a suction leak. Spray WD 40 on the joint. If engine speeds up, you've found your leak. Repair with High Temperature Silicone after a thorough cleaning.

The governor went to full throttle due to the engine slowing down. You are not getting the power you need at the generator.

JimL

* This post was edited 08/11/09 06:37pm by Generator Jim *

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