Generator wont run

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coachmen_leprechaun

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Joined
Apr 9, 2019
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4
Onan MicroLite 4000 series/ Model KY  Spec P
My parents have a 2015 Coachman Leprechaun with a Cummins Onan generator.  The coach has been used frequently, however the generator hadn't been used (about 2 years since last start up due to my father needing electrical hookup for a health condition).  the carburetor had to be replaced as it was gummed up and not salvageable, however the set will still not achieve idle.  It cranks, fires starts, revs up, then dies.  only occasionally does it stay running, but it is anything but steady and revs up and down until it cuts out.  i have not replaced the fuel filter, but i did a volume test and it was putting out more than enough fuel.  I back probed the fuel pump and verified it was getting a full 12 vDC.  The air filter was also replaced. 
Any ideas on what my next steps would be in trouble shooting?

I should also mention i am a (fairly new) technician trained for automotive diagnostic and repair and i will be the first to admit I am getting my butt kicked by this thing.
 

Arch Hoagland

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Jul 11, 2014
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4,031
Location
Clovis California
I add five cans of Seafoam to my gas tank once a year before a long trip and run the generator at least an hour while burning through that tank. Haven't had any problems for 14 years.

Perhaps you should try the same thing. $7.00 a can at Walmart.

 

stevensc

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Feb 10, 2016
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114
Location
Spartanburg, SC
coachmen_leprechaun said:
1/2 a tank. I even used an OTC scan tool to set the level percentages to make sure

Are you using the same gas that gummed up the carb in the first place?

Disclaimer - I am not familiar with this set-up.  Does the gen have it's own fuel supply?
 

coachmen_leprechaun

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Apr 9, 2019
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the engine was only reading code 3 for the times it would rev and die.  when it ran and just revved it was code 14 (improper frequency).  as for the gas, any old gas was pumped through when we did a volume test on the system to ensure it was good fuel getting through.  the set uses the same tank as the rig
 

phil-t

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Jul 10, 2017
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1,414
Location
Ogdensburg, NY
Improper frequency - there is a sensor that will shut down the genset if the frequency is not right. 
Mine stemmed from bad brushes on the generator.  A relatively common occurrance on gensets that have been sitting idle for extended periods.
 

phil-t

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Jul 10, 2017
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Location
Ogdensburg, NY
Well, it was done at the Cummins Repair shop in Albuquerque, NM.  They ran the diagnostics, mentioned the frequency thing and did a teardown of the unit for troubleshooting. Brushes were burned.
If yours is running but irregularly, that could account for the frequency thing and the shutdown.  Not saying the brushes are your problem, just mentioning the frequency thing, and if the code is pointing to that?
 

nfredrick

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Mar 13, 2017
Posts
51
perhaps try cleaning the slip rings, tool costs  about $25

https://www.partsfortechs.com/asapcart/slick-stick-polishing-tool-for-onan-other-slip-rings-p-435.html

or give Flightsystems a call , I've heard they are very helpful
https://www.flightsystems.com/troubleshooting/



 

jskco

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Joined
Mar 14, 2019
Posts
18
Had to have carburetor replaced on mine. They told me lack of use is the worst possible thing you can do for it. I was fortunate in that the issue was discovered before the papers were signed so the dealer paid for it. They have an additive for it that will help for storage (up to 6 months)
 
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