Forum Discussion

suprz's avatar
suprz
Explorer
Oct 25, 2019

Need your thoughts

My Onan micro quiet 4000 has always taken a few moments to start up when cold, but recently I have noticed that once running and warmed up after about 30 mins it starts to surge and gets progressively worse. I shut it off and it wouldn't start back up. I have the bay door open for ventilation, but I keep the access door on the generator because i know it needs it on for the cooling to work efficiently. I changed the oil and air filter recently. This last time it acted up it wouldn't start, I went outside and tried to start it from the switch on the generator itself. It still wouldn't start. I primed it and tried again and was successful after a few cranks.. But I just shut it off and let it be for now. This scenario happens if there is a load on the generator or not. I'm thinking fuel filter? Or maybe the pump stops once it gets too hot? Or vapor lock? It's only around 62 degrees today, so I don't think it's overheating.
  • DFord's avatar
    DFord
    Explorer
    Oct 26, 2019
    Mine is spec K also. It calls for 1.5L but I can't buy it like that so I ran the conversion. After it sits awhile, you can verify the correct level.

    If you change the oil and put 1qt 19oz back in, it'll be 2 teaspoons over full (if you get it all in without leaving some in the bottle).

    I had the same problem you're experiencing and ended up overfilling trying to go by the dipstick on the end of the plug. That caused some of the excess oil to end up blowing out the air cleaner breather tube. Now that I've got the right oil charge, that's not a problem anymore.
  • suprz's avatar
    suprz
    Explorer
    Oct 26, 2019
    DFord wrote:
    It's hard to believe that so many ask for help with a problem yet give so little information about the equipment. There's no way to give a correct answer about an Onan Generator without knowing the complete model, serial number and "spec".

    I have an Onan Micro Quiet 4000 generator on my MH. The capacity of the oil sump is 1.6 quarts (or 1 quart 19 ounces).

    Because air can get trapped in the crankcase, it can effect the apparent level of oil when checking it through the oil fill hole. That trapped air can be negative or positive making the oil level appear to be high or low at the oil fill.

    The best way to check the oil level is to do it first thing in the morning before starting it when pressures have equalized.

    The best way to make sure you've got the correct amount of oil in the crankcase is to drain it and refill it with 1 quart, 19 ounces of fresh oil.


    It is a spec "K"
  • DFord's avatar
    DFord
    Explorer
    Oct 25, 2019
    It's hard to believe that so many ask for help with a problem yet give so little information about the equipment. There's no way to give a correct answer about an Onan Generator without knowing the complete model, serial number and "spec".

    I have an Onan Micro Quiet 4000 generator on my MH. The capacity of the oil sump is 1.6 quarts (or 1 quart 19 ounces).

    Because air can get trapped in the crankcase, it can effect the apparent level of oil when checking it through the oil fill hole. That trapped air can be negative or positive making the oil level appear to be high or low at the oil fill.

    The best way to check the oil level is to do it first thing in the morning before starting it when pressures have equalized.

    The best way to make sure you've got the correct amount of oil in the crankcase is to drain it and refill it with 1 quart, 19 ounces of fresh oil.
  • Charley67's avatar
    Charley67
    Explorer
    Oct 25, 2019
    I would look at the spark plug. If that’s the culprit it would be a cheap fix.
  • suprz's avatar
    suprz
    Explorer
    Oct 25, 2019
    I was just watching a youtube video that describes the problem with the generator. It seems that the oil dipstick is incorrect on these gens. I did an oil change recently and put the oil to the full mark. According to what I have read, and watched, the oil can be too full and cause the issue I have described. In any case, I have suctioned out enough oil so the oil level now reads in between the full and low mark on the dipstick. I will try the generator again tomorrow and see if that has any effect.
  • time2roll's avatar
    time2roll
    Nomad
    Oct 25, 2019
    If an Onan tech wanders by they are going to want the exact model and serial numbers.
  • Matt_Colie's avatar
    Matt_Colie
    Explorer II
    Oct 25, 2019
    Suprz,

    It might just need a spark plug or the carburetor cleaned. Find a local small engine shop and get them to look at it. Onan engines are used all over the place, and the can probably supply aftermarket parts that Mr. Cummins is not so proud of.

    Matt
  • suprz's avatar
    suprz
    Explorer
    Oct 25, 2019
    jplante4 wrote:
    Fuel filter or fuel pump. The filter is cheaper and easier. Is there more than a quarter tank of fuel?


    Yes, a bit over 1/2 a tank, that has been treated with Seafoam
  • jplante4's avatar
    jplante4
    Explorer II
    Oct 25, 2019
    Fuel filter or fuel pump. The filter is cheaper and easier. Is there more than a quarter tank of fuel?

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