Good Sam Club Open Roads Forum: Onan 4000 MicroQuiet - Quasi No Start (new carb needed?)
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 > Onan 4000 MicroQuiet - Quasi No Start (new carb needed?)

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Powertour

Nevada

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Posted: 09/22/20 05:26pm Link  |  Quote  |  Print  |  Notify Moderator

Searched high and low & can't seem to find an answer to what I have going on.....

Generator came with my '15 RV. 160hrs on it, most before I bought it.

Plenty of spark. Plenty of fuel flow as tested with fuel line off carb & using prime function. New air filter and spark plug in it.

The thing will only start (hot or cold) if I drain the float bowl & crank it over with the float bowl screw open. Once it fires off I can close the float bowl drain screw & it will stay running.

Never seen anything like it in decades of off-road bike/quad carb'd stuff.

Float bowl stuck? Need a new carb?

Thanks in advance for


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enblethen

Moses Lake, WA

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Posted: 09/22/20 06:30pm Link  |  Quote  |  Print  |  Notify Moderator

Float could be stuck or needle has come loose from the float arm.


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352

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Posted: 09/22/20 06:46pm Link  |  Quote  |  Print  |  Notify Moderator

Get some Sea Foam into the system. Give it a week. Try it. If it does not start give it another week. Great stuff.


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Powertour

Nevada

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Posted: 09/22/20 07:01pm Link  |  Quote  |  Print  |  Notify Moderator

enblethen wrote:

Float could be stuck or needle has come loose from the float arm.


If one of these is the case is it straight away new carb time?

Thanks for the input!

enblethen

Moses Lake, WA

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Posted: 09/22/20 07:16pm Link  |  Quote  |  Print  |  Notify Moderator

No, it is time to remove the bowl, see if float is left in bowl or still attached to body with small pin.
It is possible as other poster stated that debris could be in line or between needle and seat.
You could carefully remove pin, float and needle. Spray brake clean or carb cleaner into opening. With needle removed, crank over genset to check for fuel flow into bowl.
A good small engine (lawn mower) shop can go through carb.

Powertour

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Posted: 09/22/20 08:07pm Link  |  Quote  |  Print  |  Notify Moderator

enblethen wrote:

No, it is time to remove the bowl, see if float is left in bowl or still attached to body with small pin.
It is possible as other poster stated that debris could be in line or between needle and seat.
You could carefully remove pin, float and needle. Spray brake clean or carb cleaner into opening. With needle removed, crank over genset to check for fuel flow into bowl.
A good small engine (lawn mower) shop can go through carb.


Gotcha. I was under the impression these bad boys were kinda 'sealed' units. I've done a ton of carb work on my motorcycles, quads, and buggies over the years. Shall dig into this now that I'm hearing you can get to the jets and stuff.

Home Skillet

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Posted: 09/22/20 08:17pm Link  |  Quote  |  Print  |  Notify Moderator

I've tried to rebuild mine at several different times. Never did work. I think the solenoid in the float bowl is the culprit.

Getting parts for these generators are getting impossible.
I tried to buy a fuel pump to keep as a spare. It has been discontinued.


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johntank

North MS

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Posted: 09/22/20 10:02pm Link  |  Quote  |  Print  |  Notify Moderator

Home Skillet wrote:


I tried to buy a fuel pump to keep as a spare. It has been discontinued.


If it's a Onan give Cummins a call they should be able to give you a replacement part no. for your discontinued pump.

jdc1

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Posted: 09/23/20 08:41am Link  |  Quote  |  Print  |  Notify Moderator

Home Skillet wrote:

I've tried to rebuild mine at several different times. Never did work. I think the solenoid in the float bowl is the culprit.

Getting parts for these generators are getting impossible.
I tried to buy a fuel pump to keep as a spare. It has been discontinued.


When I had my old motorhome, I just went down to O'Rielly's and bought an off the shelf low psi fuel pump for my Onan. Worked great. And only cost $15.00

Chum lee

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Posted: 09/23/20 08:59am Link  |  Quote  |  Print  |  Notify Moderator

The float bowl on most carburetors must be vented to the atmosphere to work properly. From your description, it sounds like your float bowl vent might be plugged or the float itself (needle and seat) is stuck. 160 hours use in 5 years is low, IMO. Is this genny being exercised regularly? (I suggest 20 minutes, once a month, every month)

Chum lee

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