Onan Generator not getting gas.

[NC Eagle]

Hi Folks
I'm a newby here ,this is my first post.
I have a 1999/2000 Pace Arrow Vision on a Ford chassis e/w an Onan Marquis 7000 Generator. The coach has been sitting for about 4 months and the generator has not been started since then. I have tried to start it without having much luck. I removed the air filter and sprayed some starter fliud in the carburator,the generator will run for a very short time on the starter fluid  but it is not getting any gas.The coach has a 1/2 tank of gas and the fuel pump fuse is good.I removed the fuel line that goes into the fuel filter (the one coming from the fuel pump)and cranked the generator over, there is no fuel coming out of the hose from the fuel pump.

Is there a way to prime the fuel pump on this generator?  No one around here seems to know!

My next step will be to remove the gas line from the gas tank to the fuel pump to make sure there is fuel to that point,(I am assuming the gas is fed by gravity to this point ), if there is, I suspect the fuel pump is gone and will need to be replaced.

Any suggestions will be greatly appreciated !
Thanks
Pete V (Aka NC Eagle)

 

[Jim Godward]

How much fuel is in the gas tank??  Most generators must have at least 1/4 tank to run as the line does not go all the way to the bottom of the gas tank.  If there is fuel, apply suction to the line before the fuel pump to get gas.  If still no gas, bad line!!  Place a line to the fuel pump into a container with gas and try the pump.  If it does not work, get a new pump.  If it still doesn't work, clean the carb.

 

[John From Detroit]

Step one is always the same, FILL THE TANK

Traditionally the tanks on motor homes have dual outlets, one outlet is around the quarter tank level the other is, the"Empty" point

Gas gages are... Well... You ever notice how the gage goes well past the FULL mark when you fill the tank..  Two words that do not go well together are FUEL GAGE and ACCURACY unless, of course it is a sentence like this or "The least accurate gages in the world are fuel gages,  Those who believe in them often go for long long walks"

So FILL YOUR TANK.. Then try again.

 

[Karl]

Hi Pete,
There is a separate fuel line coming from the main gas tank, and it is not fed by the regular fuel pump. The generator has its' own electric fuel pump which sucks fuel from the tank. The fuel takeoff from the main tank is located about 1/4 from the bottom of the tank to prevent your generator from running the tank dry and preventing you from being able to drive to a gas station to get filled up again. I know you said you had 1/2 tank, but make sure you do. If so, disconnect the line to the generator fuel pump, place the open end in a suitable container, and have someone try to start the generator. You should get fuel flowing into the container. If not, you have a blockage or leak between the pump and the tank (could be a blocked fuel filter), or the pump is not working. Carefully try sucking on the end of the hose to see if you get gas.  No, and you create a vacuum in the hose? Blockage.  No, and you get air? Not enough fuel in tank or line has a leak or split somewhere.  Yes (you get fuel)? Pump is not working. There may be a fuse for the pump located near it, or somewhere in the engine compartment. Check it. If the fuse is good, you can test the pump as follows: Disconnect the wire going to the pump. If there are two wires, one is the ground and we don't care about it (but check it to make sure the connection is clean and secure). Place the hose end back in the container you used before. Connect a fairly long piece of wire to the pump connection you removed the wire from, and another long piece of wire to the positive (+) terminal of the battery. While you're holding the hose in the container, have someone else touch the battery positive wire to the wire coming from the pump. Make sure they are well away from the pump to avoid any spark ignition of gas or gas fumes. You should hear the pump operate and gas come out of the hose. If not, replace the pump. May sound complicated, but it's really not. Any questions?
Good luck!

 

[Ron]

I would go along with Johns suggestion and fill the fuel tank, then try again.  Hopefully you will find all is well.

 

[NC Eagle]

Thank you all for your suggestions. Tomorrow I will fill the tank and see if that helps. If not then I will climb back under the coach to see what I can see.
Thanks again.
Pete V

 

[NC Eagle]

Karl,
I filled the gas tank-still no generator!
I now have a question,does it require suction to get gas directly from the gas tank? Is there some kind of demand valve where the fuel line enters the tank? I have disconnected the tank to fuel pump line from the fuel pump and I get no gas flowing from the tank.
If I understand this correctly the fuel pump provides two funtions 1)Suck fuel from the main gas tank and 2) pump that gas through the fuel filter into the float bowl of the carburator. Correct?
Tomorrow I will attempt to ascertain whether the fuel pump is creating a suction or not,I feel the pumping side of the pump is working correctly as I can feel air pulsating from the fuel line. I'm going to put some gas in a container and submerge the end of the hose in the gas ,when I turn over the generator the fuel should be sucked out of the container,right?
I also noticed the short piece of rubber hose going from the fuel pump to the rigid fuel line that ultimately goes to the gas tank is very cracked,this could be the culprit ,causing a vacuume leak. I will let you know how I make out.

Thank you for your help,as you can tell I am not very fariliar the inner workings of an motorhome!
Pete V

 

[KodiakRV]

... I also noticed the short piece of rubber hose going from the fuel pump to the rigid fuel line that ultimately goes to the gas tank is very cracked,this could be the culprit ,causing a vacuume leak. I will let you know how I make out.
...

I'm betting that's the problem.

 

[Karl]

Pete,
If you are feeling air coming out of the pump rather than gas, that cracked line is almost surely your problem. You could check the pump by submerging the far end (the one that goes directly into the gas tank) into a container of gas and make sure gas comes out the other (generator) end. Hopefully you won't have to drop the gas tank to get at the connection, but I wouldn't count on it. Good luck!

 

[BIGDOG]

Try starting the coach motor and then try to start the generator while the engine is running. My Genset sometimes will not fire unless I start the coach engine first. Thereafter, it will start. I haven't really thought it entirely through, but it works.

BD

 

[Lou Schneider]

I now have a question,does it require suction to get gas directly from the gas tank?

I also noticed the short piece of rubber hose going from the fuel pump to the rigid fuel line that ultimately goes to the gas tank is very cracked,this could be the culprit ,causing a vacuume leak. I will let you know how I make out.

Most gas tanks have their outlet at the top of the tank and drain via a dip tube inserted down into the fuel.  This requires fuel to be sucked up to the top of the tank before any will come out.  They're designed so a leaking hose will cause the fuel flow to stop from the loss of suction instead of having fuel flow out of the tank through the leak.

Sounds like you've found part, and maybe all of the problem in that cracked hose.

 

[NC Eagle]

YA-HOO  My generator is now working like a charm.  It was the hose, I took it off and it was in really bad shape. I replaced it and the generator
started right up.
Thank you all very much.

Sincerely
Pete V

 

[Karl]

Pete,
Glad to hear that! The new hose should last at least through the next generation : (Sorry; couldn't resist!)

 

[Ron]

Good to hear you got it fixed. Thanks for the follow up.