Onan 5000 not getting fuel

[cm2785]

Hey guys, I have a 96 Bounder with an Onan Marquis 5000. It has 400 hours on it. It started about two months ago and now isn’t getting any fuel. I have over a half a tank. I noticed there is an electric fuel pump behind it but have no idea if that is working. The little 10 amp fuse is good, but when I take the fuel line going to the carb from the pump it’s dry. Can anyone offer any advice? Thanks!

[Dutch_12078]

That "Genuine Onan" fuel pump was not made by Onan. When the fuel pump failed on our previous Onan Marquis 7000, I found the identical pump on Amazon with the same Carter part number on it that the Onan pump had under the Onan paint. The Carter pump was about $80 instead of the $300+ Onan price. If the fuel pump dies on our current Onan 5500, I'll likely just replace it with a universal low pressure pump from NAPA, etc.

[DiskDoctr]

Congrats on your repair and your new rig. Sounds like you're well on your way :C

[cm2785]

Hey guys, I installed the new fuel pump this morning and the generator fired right up! Just goes to show you just because an electric fuel pump runs and sounds fine doesn’t mean it actually pumps any fuel!

As for the price: I bought this 96 Bounder 34j with 11k miles for $11,200. I hadn’t had an RV for over ten years and needed all new gear. I took 30k out for this, spent the 11.2 on the RV and the rest on upgrades (video in motion satellite, New HDTV’s, lte, Wifi, cell, etc) and all the gear I needed. Most of what I bought can be taken to a newer rig when I decided to upgrade but for now I just want reliable use as I may end up living in the unit for a while during house construction. I’d much rather spend the extra $225 and get genuine Parts and mount it correctly etc then rigging an in-line pump and wiring it in. This pump has a valve on the output that kills the pump if pressure is too high so I don’t even know how I would have wired that into the new aftermarket pump plus the rubber mounted bracket for this pump seemed really nice.

Also, after speaking with Onan this is an updated pump that uses metal instead of hard plastic impellers so it should be very reliable. It took about twenty minutes to break in and quiet up a little and works great!

[DiskDoctr]

$300, ouch. I should have mentioned that most standalone pumps would work in the under $75 range. Sorry.

But at least you have a solution that you are comfortable with :C

[cm2785]

Thanks but I already ordered the correct pump and it should be here today.

[enblethen]

Thanks for the update!
I would think about an electric pump adjacent to the genset and not an Onan specific exact replacement.

[cm2785]

Hey guys, so I pulled the wires off the fuel pump and jumped it and it fired right up... I was pretty bummed out thinking my fuel line from the pump was bad but from what I can see it’s a fairly new rubber line at the tank going into the original metal line. Anyway, I pulled the hose off the metal line and put it in a fuel Can with fuel and it ran fine but wouldn’t suck a single drop of the fuel!! So I guess my pump runs but doesn’t suck anymore... so long story short and $300 later a new genuine Onan pump will be here tomorrow!

[mfox20]

enblethen wrote:
You could attach a hose to the inside of pump into gas can to see if it picks up fuel.
You could use this to fire up the genset to insure pump is providing sufficient fuel.

X2,

This is how I determined that my fuel line from the tank was deteriorated and my fuel pump was good.

[Matt_Colie]

The alcohol in current "motor fuel" will play havoc with all the rubber parts. Plan to replace all the rubber lines and the pump and rebuild the carburetor in the near future.

I did and the Onan has been great ever since, but mine is a little older.

Matt

[DiskDoctr]

Many of these use a diaphragm style fuel pump. The alcohol in the fuel rapidly makes the diaphragm stiff and deteriorates.

A replacement pump is in the $40-$50 range and is quite simple to replace.

A button with an automotive relay is fairly easy to rig up as a prime button- if your STOP button doesn't prime for you.

Weird wording...Like hitting "Start" to shutdown Windows 😉

[mowermech]

1995brave wrote:
On some models of the Onan generators you can hold the Stop button on the generator and it runs the pump to prime the generator, check your manual.

yes, that.
Also, many later models of Onans have a light in the switch rocker. When there is a problem, that light blinks in a certain pattern, such as 3 blinks, pause, 4 blinks, long pause, start over. this is a troubleshooting aid. try to start the generator, then watch for the blinking light.I didn't know this until the belt broke on my Onan 5500 and it quit. The blinking light told me "No power output".

[1995brave]

On some models of the Onan generators you can hold the Stop button on the generator and it runs the pump to prime the generator, check your manual.

[enblethen]

You could attach a hose to the inside of pump into gas can to see if it picks up fuel.
You could use this to fire up the genset to insure pump is providing sufficient fuel.

[cm2785]

That’s exactly what I was just thinking. I have a little 12v test battery and I’m going to undo the wires on the pump and jump it to the battery and see what’s what. Then we’ll know.