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Jerry_Amerson1's avatar
Jerry_Amerson1
Explorer
Aug 28, 2015

Onan 4000 GenSet Emerald Plus - Carb Cleaning

I'm working on this unit and have finally got the fuel filter and pump out and I'm tempted to move them to the outside of the sound panel at the rear of the Generator which will make changing either much easier.

I'm also going to try and clean the carb, but taking it off looks to be more work than I want right now, may have to but want to try a couple of things first. If any of you have done this for a similar Gen let me know, or let me know if it's not a good idea.

First, there is a nut on the bottom of the float bowl, and I think if I take it off I should be able to drop the float bowl down and see if there is any gunk in it....is that OK to try?

Second, I'm going to change the air filter anyway so I thought I would try spraying some carb cleaner directly in the intake with the Gen running to maybe clean out and gunk in the jets...is that safe?

Thanks for your help.
Jake
Class C
  • Jerry_Amerson1's avatar
    Jerry_Amerson1
    Explorer
    Sep 28, 2015
    I finished putting the new fuel pump, fuel filter and air filter in this weekend and mounted the pump and filter on the outside of the sound wall so they will be very easy to change in the future.

    I also got the Chemtrol B12 and mixed 2oz with a fresh gallon of gas. When I started it up I had the same problem, need to choke it to keep it running. If I don't hold the choke almost closed the unit surges and the governor tries to keep it running but it finally dies. This is with no load at all on the unit, and it only runs for a minute or so.

    I'm thinking about taking the bowl off the carb to clean it out but I don't see an easy way of doing that. Does anyone have any suggestions as to how to safely do that. There is a nut on the very bottom of the carb that looks like what will loosen the bowl.

    If anyone has any other suggestions I'm open to them.
    Thanks for your help
    Jake
  • Jerry_Amerson1's avatar
    Jerry_Amerson1
    Explorer
    Sep 01, 2015
    I have the fuel pump and filter coming, along with a new air filter and oil filter. I'm going to reroute the pump and filter to the outside of the rear sound wall of the generator so it will be much easier to service in the future. I'm also going to run some Chemtrol B12 through the carb once I get things in place and see if my problem clears up.

    Thanks for the help, all!!
    Jake
  • deprived's avatar
    deprived
    Explorer
    Aug 31, 2015
    Here's somethink interesting:
    http://inlandempire.craigslist.org/rvs/5191773221.html

    I am unaware of Japanese-make Onan carbs. Hmm - I wonder if this guy is for real?
  • deprived's avatar
    deprived
    Explorer
    Aug 31, 2015
    tboss wrote:
    I went to AutoZone just by chance to see if they had a unit I cld use and to my surprise they had the exact unit I was taking off ,,same numbers and filter.


    You wouldn't happen to have those numbers, would you? I just check Autozone for # A042P619 and came up with nothing.

    I ended up getting a rebuilt carb off eBay for $165, which is insane, but at least it's cheaper than the new ones Onan sells.
  • tboss's avatar
    tboss
    Explorer
    Aug 29, 2015
    hey dude, I had to service my onan 4000 2 yrs ago and decided It needed a new filter and pump, I went to AutoZone just by chance to see if they had a unit I cld use and to my surprise they had the exact unit I was taking off ,,same numbers and filter. The unit cost me 65.00 instead the 250.00 Onan wanted. Try them first maby if they don't have it in stock they will order it for you,,,good luck my friend...

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