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JSS1439's avatar
JSS1439
Explorer
Jul 29, 2014

Cummins Onan Generator running ruff at start up

Hi all, I have a Cummins Onan 5500 generator model HGJAB Spec E that on start up runs very ruff and smokes like crazy. It will stall out and give a 37 code about 3-4 times before eventually smoothing out and running all day long like nothing is wrong after about the 5th start up. It acts like too much gas is getting dumped into the carb at start up for some reason and I'm not even priming it. Any ideas what could be causing this? It only has 170 hours on it and I've already ran Sea Foam through it.

Thanks for your time,
Scott

14 Replies

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  • AK49er's avatar
    AK49er
    Explorer
    Jul 30, 2014
    My genny doesn't display codes, its on a class B. I was also thinking sticky choke but haven't put in the time to check it out yet. Mine is located under the van in the rear and for a fat guy like me its kind of a pain to get to. Was hoping someone would chime in and say: yep, that's it and this is how you fix it! Wishful thinking!
  • JSS1439's avatar
    JSS1439
    Explorer
    Jul 29, 2014
    AK49er wrote:
    Hi Scott, I have a little 2.8 that does the same thing sometimes, I am waiting for one of the Onan Guru guys to answer your question so it will help me.


    Really... Are you getting the same 37 code also?
  • AK49er's avatar
    AK49er
    Explorer
    Jul 29, 2014
    Hi Scott, I have a little 2.8 that does the same thing sometimes, I am waiting for one of the Onan Guru guys to answer your question so it will help me.
  • JSS1439's avatar
    JSS1439
    Explorer
    Jul 29, 2014
    Was just looking at the service manual and wondering if it could be the automatic choke out of adjustment. Which would possibly explain why it runs so good once it warms up a little. Thoughts?

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