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Onan Generators

What Have You Done to Your Onan Generator Today?


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  #1891  
Old 10-20-2015, 07:56:56 AM
Leon N. Leon N. is online now
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Default Re: What have you done to your Onan generator today?

I have a suspicion that my Garretson is getting lazy and is responding erratically to the Onan suction pressure.
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  #1892  
Old 10-20-2015, 12:02:30 PM
len k len k is offline
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Default Re: What have you done to your Onan generator today?

Could be oily inside from years of use. The oils that eventually deposit from nat gas use are sticky and tacky.
At least here they are.

Or just the lube grease has gotten old and dried up.
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  #1893  
Old 10-20-2015, 12:24:14 PM
Leon N. Leon N. is online now
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Default Re: What have you done to your Onan generator today?

Reason I suspect it is the Garretson and not my JB is because the JB can be warmed up and just running perfectly at a constant no load speed and then for a few seconds it will cough, and hunt and vary speed then it will settle down for a while and then maybe a few minutes later go through another tirade. I suspose then govenor sensitivity is a tad to sensitive. However, the JB does meet the 2 second recovery requirement from NL to FL and the droop is only about 2 HZ.
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  #1894  
Old 10-20-2015, 12:27:35 PM
len k len k is offline
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Default Re: What have you done to your Onan generator today?

As a test you could try marking the gov adjustments and reducing the sensitivity to see if that stops the occasional tirade.

I assume this cough still happens after you replaced your spark coil condensor.
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  #1895  
Old 10-20-2015, 02:31:02 PM
Leon N. Leon N. is online now
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Default Re: What have you done to your Onan generator today?

Len K, Yes.
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  #1896  
Old 10-20-2015, 06:52:12 PM
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Jim McIntyre Jim McIntyre is offline
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Default Re: What have you done to your Onan generator today?

Hmm. I don't see how measuring the Garretson output pressure will resolve this. Even if it does vary, there'd be no easy to prove whether that was the cause or an effect of the throttle position changing.

If I was worried about it, I'd just replace the old Garretson. They have a rubber diaphragm that can't be expected to last forever.
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  #1897  
Old 10-20-2015, 06:54:49 PM
len k len k is offline
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Default Re: What have you done to your Onan generator today?

Don't they have rebuild kits for the reg? There's not much inside them, would guess you just want to replace diaphragm, maybe seal on valve seat. and lube pivot.

Maybe put Permatex 2 (for car engines) on the OD of diaphragm to seal to case, that stuff seals just about everything.

Last edited by len k; 10-20-2015 at 07:06:32 PM.
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  #1898  
Old 10-20-2015, 07:21:01 PM
Jack Hottel Jack Hottel is offline
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Default Re: What have you done to your Onan generator today?

Don't forget that at the output of the demand regulator is vacuum. With a manometer connected, a hiccup in the regulator may empty the manometer into the carb.
Jack Hottel
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Old 10-20-2015, 07:27:55 PM
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Default Re: What have you done to your Onan generator today?

Quote:
Originally Posted by len k View Post
Don't they have rebuild kits for the reg?
Somebody might sell them, but not Garretson. I have to think it's a liability thing. The latest KN regulators I bought had the pressure adjust screw lock-tite'd to make it REALLY hard to adjust...

Not saying it's good or bad, just the way it is..

New KN's are around $50, and come with a primer button.

I buy 'em here:

http://www.carbturbo.com/
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Old 10-20-2015, 07:50:28 PM
Leon N. Leon N. is online now
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Default Re: What have you done to your Onan generator today?

All good comments. You know, the condition I am observing can be artificially created by miss adjusting the carb main metering jet. That is why I suspect the KN2. Just remembered, I do recall purchasing a KN2 rebuild kit. It is out in the shed somewhere. But I don't relish the idea of taking down the KN2. I think I will try to desensitize the govenor first. That is the easy way out. All I need is a screw driver and what a 5/8 box wrench. But then I will have to run a load test again to make sure the frequency stays within spec. More later.
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