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Genset surge
Onan Emerald 3  6.5 kw lpg is surging +/-20v untill nearly fully loaded, after extremely rough road trip will check plugs, points and wires, air filter looks good. Oil ok. Any other suspects?There is a thread about rear bearing, about to order...

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Re: Genset surge
Reply #1
Is this a liquid lp generator or vapor lp generator (look on the lp tank to see if there is a liquid tap for the generator)?

  • DavidS
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Re: Genset surge
Reply #2
When you say rough trip do you mean a few things went bad or the drive was off road?

Off road could be a wire wiggled  loose.

Re: Genset surge
Reply #3
When you say rough trip do you mean a few things went bad or the drive was off road?

Off road could be a wire wiggled  loose.
Eastbound I-40 out of Barstow, potcraters 100' on center. Lots of...

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Re: Genset surge
Reply #4
Vapor generator, I can see the carb butterfly cycling, is there a way to dampen the movement, or is something else going on? It appears there may be a possibility that this unit may slide out somewhat to allow service to the back cylinder. Is it...

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Re: Genset surge
Reply #5
    Phred
If it's anything like mine (6.5 onan) the gen-set does not slide out as there are 2  1/4 bolts tying the rails down. You can work on the rear cylinder but it's a back strain deal with the access door in the way  :headwall:
If you got the manuals...

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Re: Genset surge
Reply #6
There is a sensitivity adjustment on the governor and also if it is to lean will cause it to surge.

Re: Genset surge
Reply #7
Interesting-- at least in 1993, they were using LIQUID LP generators (easy to tell because there is a liquid tap on the LP tank).

There are some very well known issues with these.  But if yours if vapor they would not apply.

Re: Genset surge
Reply #8
Ok, 3 manuals don't show adjustments for surging no reference to governor sensitivity adjustment, there appears to be a adjustable rod end on the governor linkage that may be able to shorten the stroke of movement somewhat. And the main jet...

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Re: Genset surge
Reply #9
There should be a screw on the carb body that if screwed in will increase engine speed sometimes you can run it very close to the stop and with less area to move might stop the surge. Which model of Onan do you have? I am not sure if it is an NH...

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Re: Genset surge
Reply #10
It's a NHE, accessable spark plug is very light tan almost white, so I may need to fatten the mixture a tad bit. There is a right angle knurled valve with a lock nut on that would appear to adjust/distribute  propane in a radial fashion into the...

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Re: Genset surge
Reply #11
No muffler less back pressure would run lean.

Re: Genset surge
Reply #12
When you get all done, check your cycles to be on 60. Some of these adjustments may effect engine RPM.

Re: Genset surge
Reply #13
The color of the spark plug sounds right for propane.

Re: Genset surge
Reply #14
Was reading your original post. If generator has been operating normally and is suddenly erratic, I would check governor for either a sticky mechanism or an excessively worn mechanism. I wouldn't think the sensitivity adjustment wouldn't suddenly...

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Re: Genset surge
Reply #15
Was reading your original post. If generator has been operating normally and is suddenly erratic, I would check governor for either a sticky mechanism or an excessively worn mechanism. I...


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Re: Genset surge
Reply #16
Doubt it needs grit back but a loose rod end will definitely cause a problem. Looseness from wear is different than freedom of movement from being clean and lubricated.

Re: Genset surge
Reply #17
Wow my old info brain is getting a workout.

I think the play in the governer rod does cause surging.  If held tight I think the surging stops

Re: Genset surge
Reply #18
Bearings worn. Likely replaceable.   Governors like smooth operation with tight clearances to provide dampening affect. Looked at parts manual.  Rod end worn or a hole in arm being too big could be your problem.

Re: Genset surge
Reply #19
I believe I have found the sensitivity adjustment, you can alter governor spring tension via a Phillips head screw hidden under a lever arm. I will try racer stainless safety wire to tighten the clearance on the plastic rod end. After that I may...

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Re: Genset surge
Reply #20
I just discovered the OEM coach wiring to the ATS from the 6.5 kw genset is 12 guage, lots of voltage drop. No wonder when the front a/c kicked on genset, all hell would break loose and the genset would shake the whole coach and surge for about...

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Re: Genset surge
Reply #21
While reading another post, it just hit me, thought it had to be play in the old linkage, never hooked up a manometer to see what the gas pressure was, because it's not listed in trouble shooting guide. This year it seems worse. hell it may be...

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Re: Genset surge
Reply #22
While reading another post, it just hit me, thought it had to be play in the old linkage, never hooked up a manometer to see what the gas pressure was, because it's not listed in trouble...


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Re: Genset surge
Reply #23
 Repair the muffler before changing the jetting .  Reduce the slack in the control rod if it looks out of range.  IMHO.

Re: Genset surge
Reply #24
Also check the governor sensitivity adjustment. Sometimes if the low speed adjustment screw is run a little closer to the stop on the throttle shaft so that it doesn't have as much room to oscillate that can help with surging. Also if to lean...

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