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WBandJ · 10-19-2014, 04:57 PM

After a bit of troubleshooting, I discovered that the fuel pump on our Onan MicroQuite 4000 KY needed replacement. At first I thought that I would have to drop the genset so that the cover could be removed to gain access to the fuel pump. After dreading this task for several days, I decided to try and remove the pump while the genset was still in place. There are two screws that mount the controller / solenoid assembly to the getset frame. With the removal of these screws and the cables attached to the solenoid, I was able to snake the controller / solenoid assembly out of the genset. This provided enough room to access the fuel pump. Reassembly was bit more challenging, I had to remove the solenoid from the controller before I could squeeze everything back in place. So with luck and patience, the OEM fuel pump can be replaced without dropping the genset.

Bondad · 10-19-2014, 05:02 PM

Wild Bill - I discovered the same thing a few weeks back. Problem I had was the screw holding the pump in place was rusted and completely frozen. I ended up drilling it out from below and using a nut and bolt for the replacement. Genset is running pretty well now but does "surge" after running for about 20 minutes. I'm still trying to figure out that issue.

krivanj · 10-19-2014, 08:10 PM

I had this fuel pump problem on my 4000 ky on my last RV. I bypassed the pump using a cylindrical pump from Amazon. I mounted it under the generator in a thick piece of plastic tubing. Never had another problem. The generator was still under warranty but I could not get any authorized repair shop to look at it inside 3 weeks, so this was my fix, so we could leave for our trip. Onan 4000ky fuel pump "sucks" (or rather usually it doesn't). ��

Narflack · 10-20-2014, 06:50 AM

Quote:

Originally Posted by WBandJ

After a bit of troubleshooting, I discovered that the fuel pump on our Onan MicroQuite 4000 KY needed replacement. At first I thought that I would have to drop the genset so that the cover could be removed to gain access to the fuel pump. After dreading this task for several days, I decided to try and remove the pump while the genset was still in place. There are two screws that mount the controller / solenoid assembly to the getset frame. With the removal of these screws and the cables attached to the solenoid, I was able to snake the controller / solenoid assembly out of the genset. This provided enough room to access the fuel pump. Reassembly was bit more challenging, I had to remove the solenoid from the controller before I could squeeze everything back in place. So with luck and patience, the OEM fuel pump can be replaced without dropping the genset.

I think I may have a bad fuel pump or filter but not sure. I replaced the carb and my on an 4000 starts but quickly dies. Does this sound familiar? Pump produces fuel when motor cranks with fuel ine disconnected.

I have same thoughts as you about accessing filter and was prepared to drop the generator from Andre my 2000 coachmen mirada today. Is the solenoid assembly you are talking about the square box on tags left of the cabinet with circuit board. Not looking forward do dropping the whole think.

I am in KY too did you buy the pump locally or on line? If local where.

Bondad · 10-20-2014, 11:39 PM

I bought my pump and filter on amazon. Airtex E11007 Electric Fuel Pump for Onan Generator Set. It's identical to the onan pump at a much better price! But if you have fuel when cranking, it' might not be the pump or filter. It's possible your fuel line in collapsing. I replaced my fuel filter, pump and flexible fuel lines. One of those fixed my stalling problem. But the parts were all OEM so needed to replaced anyway. Good luck

WBandJ · 10-21-2014, 03:45 AM

Quote:

Originally Posted by Narflack

I have same thoughts as you about accessing filter and was prepared to drop the generator from Andre my 2000 coachmen mirada today. Is the solenoid assembly you are talking about the square box on tags left of the cabinet with circuit board. Not looking forward do dropping the whole think.

Yes, on our MicroQuite 4000 the controller (circuit board ) and the solenoid mounted on top of the controller is on the left side of the genset.

Have you tried to hook up an alternate fuel supply directly to the carburetor? Bypass the OEM filter and pump, be sure to disconnect the power to the pump, and let gravity feed fuel to the carburetor. If the genset runs, then you have verified that the controller is functioning. I also added some http://seafoamsales.com/sea-foam-motor-treatment/ to the alternate fuel tank to remove any varnish inside the carburetor.

If the genset runs on the alternate fuel tank and since you have already verified that the pump produces a steady stream of fuel to the carburetor, the fuel supply lines would the next area to check.

I got lucky and found a good deal on Ebay, they usually list between $70 and $100.

Retiredx2 · 10-21-2014, 11:13 AM

We had 76 hours on our Onan generator- it showed fault 17- I called Onan because it happened on a trip after 5 on a Friday - was told probably needed fuel pump replaced. Finally found a Onan tech & that's exactly what the issue was. seems the diodes (unsure of spelling) had gone bad. 76 hours on this generator.

Narflack · 10-22-2014, 05:51 AM

Quote:

Originally Posted by WBandJ

Yes, on our MicroQuite 4000 the controller (circuit board ) and the solenoid mounted on top of the controller is on the left side of the genset.

Have you tried to hook up an alternate fuel supply directly to the carburetor? Bypass the OEM filter and pump, be sure to disconnect the power to the pump, and let gravity feed fuel to the carburetor. If the genset runs, then you have verified that the controller is functioning. I also added some Sea Foam Motor Treatment (Seafoam) to the alternate fuel tank to remove any varnish inside the carburetor.

If the genset runs on the alternate fuel tank and since you have already verified that the pump produces a steady stream of fuel to the carburetor, the fuel supply lines would the next area to check.

I got lucky and found a good deal on Ebay, they usually list between $70 and $100.

It's showing a code 35, bad circuit board. 350.00 fix. A fuel pump would be a lot cheaper!

Narflack · 10-25-2014, 06:50 AM

It was the circuit board. Replaced it yesterday and while had access changed fuel filter. Neither is an easy task if you haven't done it before. At any rate it was starting and running fine yesterday. Hopefully it's fixed. Thanks for all the advice and suggestions

floridave · 01-26-2015, 03:32 PM

Had a similar issue(surging then stalling after 20 minutes) with my 4000 ky in my 2009 Monaco Monarch 30 fullslide...to replace the fuel pump, I dismounted the solenoid and swung it over, removed the 4 mounting screws for the entire gennie to jack it up a bit to get to the two screws holding the control box bracket in place...after wiggling the control box out, I removed the filter through the outside fuel line port of the gennie before dismounting the pump, so the pump just slid right out with ease..reattached the filter, replaced the one time use clamps on both ends of the pump, and reassembled..about an hour.

During the repair, I mustve inadvertently hit the breaker to OFF, because it didnt have ac power at first..oops, reset it and all is well now.

Got the part in three days from a place on ebay called "anyrvparts" for 69.99 free shipping..a genuine onan replacement. Mine was a part number 149-2311-02

After looking at (and now joining)this forum, I felt confident in doing the fix myself...thanks to all the members who have shared their experiences with the 4000, it saved me a ton of cash Im sure!

Dave G.

floridave · 09-29-2015, 04:36 PM

Update on the Onan 4000 fuel pump I replaced in January this year..I used a Onan replacement part, and after 300 hours of use it began clicking like crazy and stalling every few hours.

I ordered a new Airtex brand this time, seeing better reviews for the Airtex over the Onan.

Heres the link, and its half the price of the Onan factory part... http://www.amazon.com/gp/product/B00...ilpage_o05_s00

When I disassembled the fuel pump on the generator, the fuel line where it meets the fuel filter had collapsed partially right before the fitting, causing the fuel to be starved coming into the pump.

Since I had the pump out, and it made the noise for hours(we were in 95 degree heat and had to run it) and then ran quietly for hours at other times, I replaced it with a new one and also am keeping a universal airtex pump in the rv in case it happens again on the road.

I fired it up and it has ran fine today so we shall see how it goes.

So, if you have this problem, and replace your fuel pump, be sure to check the fuel hose end for separation, cut off a short piece to get fresh hose and reconnect tightly to avoid what I encountered this past trip.