not getting fuel to carb on Onan generator

[mcal63775]

Onan Marquis 7000 it started rough but it cleared itself out after a minute or so. Ran smooth for 10 minutes under a light load powering a small space heater and running microwave and all the interior lights on. Then it started to bog down for 3 seconds, recover , run 30 sec. bog down again, run 30 sec. bog down and eventually died. Have not been able to get it to run since. I pulled off fuel line to filter and no gas came out of filter or the fuel line. I used starting fluid to get gen to run, squirting enough to keep gen running, expecting fuel to come out of fuel line. No fuel. Is there an external fuel pump for my generator? or is it an electronic pump? Generator gets its fuel from main tank of MH.

[cbr46]

That's ok, I just finished putting mine back together last night. Looks like the main crank seal got ripped on re-assembly when the "motor" locked up last summer.

Last summer it was a complete engine tear down, no problem found (wth?) . . . . until I went to spin the generator armature (bearing had seized). DOH! Wish I had done that before tearing into the motor! That was a $23 fix for an armature bearing. This time it's an $8 fix for a crankshaft seal for not taping the ridge on the crankshaft. Good thing for the low oil shutdown sensor!

I come out cheap both times but it sure is a LOT of labor!

Glad you got "Jenny" all well again.

Aren't they fun to drop down and haul up on a work bench without any help?

Best,
- bob

[mcal63775]

Issue resolved... for now. Purchased a new deep cycle battery, got everything hooked back up and hit start button. Genset fired up, ran like a champ! Conclusion for now is that the fuel line had a hole in it and not enough voltage in battery. SO SIMPLE, yet expensive on my part replacing parts that may not have need replacing. LESSON TAKEN in stride.

[falconbrother]

I had that exact same symptom a few months ago. I cleaned out the air filter, fooled with it some, checked the plug gaps, really did nothing meaningful.. And when I put it all back together it started. Give the little choke lever a wiggle before you hit the start button. Also, sometimes I will need to adjust the altitude setting under the float bowl and when she starts turn it back to where it was originally. My old Onan almost never starts on the first try when it's been sitting a few days. I hit the start button, wait about 30 seconds and then she fires right up pretty much every time. My mechanic just shrugs his shoulders.. As long as I have a working generator, I don't really care. I use that thing on pretty much every trip we take, especially in hot weather to run the roof air.

[mcal63775]

I took a 2 hr. break, came back and put my tools away. I was getting ready to close compartment door, and I thought I'd hit start switch one more time...
and starter engaged and she cranked and cranked to the point of fuel coming out of bottom of air cleaner, but it didn't hit. So now, no fire to new plugs I suppose. Closed door and went to beer fridge. I am waving white flag for the day. I got steaks to cook.

[rgatijnet1]

mcal63775 wrote:
UPDATE: Hole in fuel line. I replace a 2 ft. section of the fuel line where it was a bit stiff, and in a bind where it hooked up to fuel pump. NOW it pumps fuel. And now another problem. It won't crank over. Like its vapor locked or something. I pushed start button and it did a one time crank and no more. The starter engaged and it acted like not enough battery. I checked voltage. 9.6 put on charger for an hour , back to good, and now the solenoid behind the starter switch is clicking rapidly when I hit start. and starter not engaging. I took plugs out and was able to turn engine over by hand. AARRGGHH.

Try using the "boost" switch on your dash when starting the generator.

[mcal63775]

UPDATE: Hole in fuel line. I replace a 2 ft. section of the fuel line where it was a bit stiff, and in a bind where it hooked up to fuel pump. NOW it pumps fuel. And now another problem. It won't crank over. Like its vapor locked or something. I pushed start button and it did a one time crank and no more. The starter engaged and it acted like not enough battery. I checked voltage. 9.6 put on charger for an hour , back to good, and now the solenoid behind the starter switch is clicking rapidly when I hit start. and starter not engaging. I took plugs out and was able to turn engine over by hand. AARRGGHH.

[turbojimmy]

mcal63775 wrote:
Bob, that is probably the case due to brittle or rotten fuel line and sucking air instead of fuel. I should get a primer bulb and extend the fuel line to see if I can gravity feed/ siphon fuel into a container. I WD-40'd the tank strap bolts already, and I may not have to drop the tank all the way down. I need just enough room to reach up in there. Being a contortionist isn't easy when you're a fat guy like me. lol. Several years ago, I dropped that tank once before to replace the fuel pump. If I would have known THEN what I know now.. well you know. lol Ain't nuthin' but a thing.

I would still blow the line out with compressed air just to make sure there isn't some sort of blockage.

If you do have to empty the tank, there is probably a fuel pump test lead that will allow you to run the pump. There's usually a test port with a Schrader valve on the fuel rail. Hook a braided steel line up to it (I don't recall the size) and pump it into containers.

I took my fuel filler tube off and siphoned out using the mouth-full-of-gas method.

[mcal63775]

cbr46 wrote:
Is it possible the tank - gen fuel line simply lost it's siphon?

Best,
- bob

Bob, that is probably the case due to brittle or rotten fuel line and sucking air instead of fuel. I should get a primer bulb and extend the fuel line to see if I can gravity feed/ siphon fuel into a container. I WD-40'd the tank strap bolts already, and I may not have to drop the tank all the way down. I need just enough room to reach up in there. Being a contortionist isn't easy when you're a fat guy like me. lol. Several years ago, I dropped that tank once before to replace the fuel pump. If I would have known THEN what I know now.. well you know. lol Ain't nuthin' but a thing.

[cbr46]

Is it possible the tank - gen fuel line simply lost it's siphon?

Best,
- bob

[mcal63775]

Folks, I just learned me a lesson, that possibly cost me $249 dollars, which was the cost of the new fuel pump. I put a new fuel line on intake side of fuel pump and ran it to a gas can, with 93 octane and stabil in it. With the fuel line disconnected to the filter, I hit the starter and fuel shot out. Reconnected to filter, got it started and she has been purring like a kitten for 45 minutes now. Genset is under a small load, with the furnace running and a small ceramic heater on high.

I wish that I would have done that with old fuel pump 1st before I spent the money for a new pump, which I may have not needed. LOL what a Dumb Arsh I is. LOL. On the upside, I don't need to worry about the fuel pump, got me some hands on intimate time with ole Gen, reaching into places I didn't think my hands could go.. Down side is I got to drop the freaking fuel tank to get to the top of tank. I Can't cut hole in floor for access, due to fresh water tank sits above the fuel tank. I will wait for warmer weather for that task!

[Geocritter]

I have the same generator.

Have you checked the fuel pump fuse located on the lower RH corner of the Generator Set Control Panel?

If you have and the fuse and connection is good you can test the pump by doing the following.

1. Disconnect the rubber line that runs from your fuel pump to your gas tank.

2. Disconnect the fuel line where it enters your carburetor and point it into an empty container to catch any discharge during subsequent testing.

3. Connect a temporary line from the fuel pump inlet into a full gas can

4. Press the start button on the side of your generator. The electric fuel pump should immediately turn on and start pumping gas from the full gas can into the empty container.

Steve

[Passin_Thru]

Don't squirt starter fluid in a gas engine. You can blow the heads clear off the engine.

[D_E_Bishop]

This may be a stupid question but, will the generator run with the engine running. There should be and evidently there is a in-tank pump, from there it goes to a pressure/flow regulator. From the P/F regulator it goes to the engine and the generator. It does not take much of a blockage any where on the line to stop the generator pump from sucking fuel out of the tank without an assist from the in-tank pump.

I would check first at the place where the fuel line "T"s off to the generator and work back to the generator pump.

It may seem silly but you're just grasping at straws right now.

[10forty2]

If no fuel is coming through the line when it's disconnected from the genset, then either you are out of fuel, the pickup line in the tank is sucking air due to deterioration or misplacement in the tank, the line itself from the tank to the fuel pump is deteriorated and is picking up air, your fuel pump has failed, your fuel filter or the fuel line is stopped up or you have a blown fuse or disconnected wire to the fuel pump. Those are really the only possibilities for the given circumstances you describe. I'd start by eliminating the simplest one and make sure I didn't have a blown fuse. Then check the filter, then the lines between the genset and the pump, then the pump and then the pickup line inside the tank.

Let us know what you find.