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Onan 2800 Micro Lite Surging


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  #1  
Old 01-31-2011, 02:13:35 AM
icarus icarus is offline
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Default Onan 2800 Micro Lite Surging

A friend brought by his MH with an Micro-lite 2800 in it. It starts and runs fine, but there is a and odd surging, especially with little load. The voltage stays relatively constant but it causes a light bulb to blink significantly. If I load it down with the roof A/C it runs better, but still not as well as others I have worked on. I have made sure that the atmosphere probe is clean and dry (LP fired unit).

I'm thinking a control board issue, but don't know where to start.

Thanks again for any and all help.

Icarus
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Old 01-31-2011, 02:57:49 AM
pegasuspinto pegasuspinto is offline
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Default Re: 2800 micro lite surging

A model and serial number will help-but generally, the mixture could be off (bad regulator, bad demand regulator, or adjustment), the governer could be out of adjustment, or there could be slop in the linkage. There could be a varying load in the RV itself, maybe the DC converter or who knows what-pop the breaker on the generator to see if it smoothes out. It's almost certainly NOT an electrical issue within the generator itself.

Robert
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Old 01-31-2011, 09:26:03 AM
Andrew Mackey Andrew Mackey is offline
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Exclamation Re: 2800 micro lite surging

Surging or hunting is usually a sign of a too lean condition. I would check the propane supply and the gas controls first. With it being so cold out, your friend may also be having a tank freeze condition, especially if the tank is below 1/4 full. As fuel evaporates, it cools, and propane will chill itself to the point where it will not vaporize readily. This becomes a big problem if it is cold out already! A quick test: As the unit is running, take a 5 gallon bucket of WARM water, and pour it in the sides (NOT THE VALVE) of the tank. See if the engine smoothes out, and then returns to hunting after a short time (Tank cools off). Also, look for frost on the surface of the tank. This is a sure indicator of a tank freeze condition. Is your friend using a grill tank for supply? if so, it is way too small to supply the engine - same reason as above, not enough area in the tank to dissapate the cold!
Andrew
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Old 01-31-2011, 11:33:47 AM
icarus icarus is offline
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Default Re: Onan 2800 Micro Lite Surging

I actually don't think it is a matter of low vapor pressure from the tank due to cold. Temps were in the 50's F the last time I tested it. I will run it again today and report back.

Icarus

PS Thanks for the tips.

T
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Old 01-31-2011, 12:32:59 PM
Descentman Descentman is offline
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Default Re: Onan 2800 Micro Lite Surging

Also check all the regulators for insect blockage in the breather ports. I have specially trained all the mud dauber wasps around here to block those ports so I can increase service calls.
Hey! the economy's down, I had to do something LOL
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Old 01-31-2011, 02:23:11 PM
icarus icarus is offline
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Default Re: Onan 2800 Micro Lite Surging

Thanks all, (It turns out to be a micro-lite 2500 but I think the same rules apply.

I ran it today with a 1500 watt load. With a kill-a-watt plugged in the freq jumps around from ~58-61, the voltage stays fairly steady at ~117 vac. After it is fully warm it seems to run fine. That said, there is considerable flicker on a conventional light bulb. I did clean the atmosphere sensor filter as it was failry plugged with dust.

I'll let you know if there are any other symptoms.

Icarus
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