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cruiser1 · 05-01-2013, 11:19 AM

Hi all.

I"m new to this forum and new to owning a 1997 LY 30ft. I need some help with my generator that will not start. It will turn over and run if I spray start fluid in the intake. But I'm not getting gas to the carburetor. The tank on the motorhome is over half full so I know that's not the problem. My question is... is there a fuel pump that sucks gas from the main tank to the generator? I'm lost and could use any help.

Thanks

Airstream12557 · 05-01-2013, 11:24 AM

I had a similar problem in my 2004 Land Yacht, but the gas tank was about 1/4 full. After filling the MH fuel tank, the generator started and ran fine.

Has your generator ran recently? Could you have a fuel filter problem? If possible, I would fill the motorhome gas tank and try it again.

Sam

Airstream12557 · 05-01-2013, 11:25 AM

I forgot; welcome to the forum. The group is very helpful and we all learn from each other.

Sam

CDONA · 05-01-2013, 11:42 AM

There is a small fuel pump on mine, it runs when I prime the system. I did have all the fuel evaporate from the genny to the fuel tank during my year in Bullhead City. I used a mity vac to pull fuel into the line up to the carb (a good thirty feet), it took awhile with a bunch of squeezes. I don't think the stock fuel pump would ever overcome that pull.
The gummed up jet in the bottom of the float bowl was the key for me to get it running again

cruiser1 · 05-01-2013, 12:56 PM

Hi Sam,

Not sure when the last time the generator ran. I'm going to say at lease 2 years ago. The fuel tank is 3/4 the way full right now. But I will have to try to filling it all the way up. I wasn't sure if there was a fuse somewhere that I was missing. We tried priming the line and was able to get a little bit of fuel to run out. But that was about it.

is.chowa · 05-01-2013, 01:47 PM

Welcome to the forum. You could do a search on this site for Onan Marquis and get some info. Check the connectors for corrosion. Given that it sat for 2 years it is a possibility that you have a gummed up carb. Mix a carb cleaner and fresh gas in a separate container and feed directly to the genny carb. See if that helps. Also on the list, change oil, filter and airfilter.

Good Luck

Steve

92landyacht · 05-01-2013, 01:52 PM

Disconnect the fuel line from the carb and crank the genset with the fuel line in a jar. See if you get fuel pumped out. If so, it's possible that the fuel in the line is stale or the carb needs to be rebuilt. If the fuel smells bad or is dark then keep pumping in short bursts until you get fresh fuel. You can also let gravity move the fuel out once you get fuel by placing the line and jar as low as possible. You may need to drop the float bowl to clean out any old fuel as well. Either way your goal is to get the stale fuel out. If no fuel after cranking a few seconds then it may be fuel filter or a bad fuel pump. At 3/4 full you should have no issues with dip tube level pulling gas. That's assuming that the gauge is accurate.

Once you do get it started verify you have full AC voltage. If not, your slip ring may need to be cleaned. Very common problem if a genset has sat for any period of time. It's the main reason that all gensets need to be
exercised once a month.

DaveFL · 05-01-2013, 03:15 PM

If the above good suggestion don't work, no fuel sucking in, it might be that it can't get into the carb, bolt under carb bowl on older models, drops it, carefully not to crush or destroy the o ring at top edge, if you have room you can drop the needle valve located above the float, squirt wd40 into the area, also take out the air adjustment needles do them.
I found seafoam from auto parts store great to mix in the jar of fuel if it is being pulled thru.
I have had genset not starting but making starting noises when battery connections or low voltage is present and not spinning fast enough to start, you might be able to use the switch on the dash to connect all batteries to help start it.
Great way to use the forum, lots of backyard mechanics on this site, good luck and happy cruising.

cruiser1 · 05-02-2013, 07:41 AM

Thanks everyone for the tips. I'm going to remove the fuel line from the generator and install it in a jar and see if that work. I will keep you posted.

Norm

Protagonist · 05-02-2013, 07:59 AM

Quote:

Originally Posted by is.chowa

Given that it sat for 2 years it is a possibility that you have a gummed up carb.

If the last fuel put through the generator contained ethanol, that's not a possibility, it's a guarantee.

92landyacht · 05-02-2013, 09:57 AM

"Also on the list, change oil, filter and airfilter."

Speaking of oil, you may want to check the oil level. On most Onan models you must have enough oil (when the unit is level) or the unit will not start. Most likely not your main cause but also a posibility.

cruiser1 · 05-03-2013, 09:50 AM

OK after messing with the generator last night I believe the fuel pump if bad. Me and a buddy ran 12 volts right to the pump and all we got was a clicking noise coming from the solenoid. Also with me touching the solenoid while he turned it over there was no clicking that I could feel. We had 12 volts going down to the fuel pump when turning over generator. So I believe it has to be the fuel pump. Would you guys agree or can I be missing something? If so. I have seen you can just pick one up at Auto Zone or O'Reillys for cheaper.

Protagonist · 05-03-2013, 10:47 AM

Quote:

Originally Posted by cruiser1

OK after messing with the generator last night I believe the fuel pump if bad. Me and a buddy ran 12 volts right to the pump and all we got was a clicking noise coming from the solenoid. Also with me touching the solenoid while he turned it over there was no clicking that I could feel. We had 12 volts going down to the fuel pump when turning over generator. So I believe it has to be the fuel pump. Would you guys agree or can I be missing something? If so. I have seen you can just pick one up at Auto Zone or O'Reillys for cheaper.

It's a start. That's the thing about troubleshooting; the first problem you find isn't necessarily the only problem. After you replace the fuel pump, you may still find the carburator gummed up, or whatever.

CDONA · 05-03-2013, 12:04 PM

I bought another fuel pump because I couldn't hear/feel the stock pump run. Plugged in the new one, same results. it wouldn't pull the thirty feet of empty fuel line. When I did get fuel to the pump it did work, so I tried the original one and it worked too. My experience, get fuel to the pump first, then clean the main jet in the bottom of the float bowl.

cruiser1 · 05-03-2013, 01:04 PM

Thanks for the responds guys. I will start by trying to get fuel to the pump first and then worry about getting a fuel pump. I will keep you guys posted.

Norm

cruiser1 · 05-03-2013, 01:07 PM

Thanks for the responds guys. I will try getting fuel to the pump first and then see if I need to get a new fuel pump. I will keep you all posted.

Norm

92landyacht · 05-03-2013, 02:00 PM

Disconnect the fuel line going to the pump first and see if you get fuel there. If fuel does not run out the line, then draw a vacuum on the line and see if you can get fuel to run freely. You can use a longer piece of clear tubing and draw a vacuum with a hand vac or your mouth until you see fuel in the line. Drop the line low and into a jar. Verify that the fuel runs freely with a natural siphon. Once flowing there shouldn’t be any air in the fuel. Keep drawing fuel until you get fresh fuel out. If you can't get fuel out, then it may be an obstruction in the fuel line or a problem with the dip tube in the fuel tank. Once you have fuel coming out of the fuel line, then reconnect the line and see if you get fuel with the pump. If no fuel then disconnect the fuel filter and see if you can get fuel that way. If no fuel then the pump is shot.
Be careful of getting the cheapest pump from an auto parts dealer. Although the pump does not have to provide a large volume of fuel it does need to be the correct pressure. Too much and it will over whelm the float. Too little and you'll run lean under load. The rated pressure should be around 4-6psi. Many have had good success using the automotive pumps. Carter makes one that is really a good quality pump that looks OEM to Onan’s pump but more like $80 v/s Onan’s $225. You could also go with a Mr. Gasket vibrator pump for around $40 but be prepared to replace it more often.

cruiser1 · 05-14-2013, 01:15 PM

Well everyone. After doing all your tips on the generator. I found out the fuel pump was bad. I replaced it and its up and running like a champ again. Thanks again to everyone with the helpful tips.

Norm

92landyacht · 05-14-2013, 02:57 PM

Glad to hear it's up and running. I'd give it a good load test now. Get as much of the rated load on it as you can. I picked up a few 1500W (qty 4) heaters just for that purpose. Run it in for at least an hour.

jcj350 · 04-21-2015, 02:46 PM

my onan 5000 is spitting fuel out of the carb, getting way too much fuel, if i clamp the fuel line with vise grips its runs/ crappy but it runs, any advice?