Good Sam Club Open Roads Forum: Onan 5500 fuel pump not priming
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 > Onan 5500 fuel pump not priming

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Rsnawder

California

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Posted: 08/18/19 09:41am Link  |  Quote  |  Print  |  Notify Moderator

Hello everyone...love to hear your feedback. I have a Georgie boy Landau 2005 with a 5500 onan generator. The generator was having problems starting so I took the RV to a repair shop and one test they ran was spraying carburetor or fuel cleaner into the front of the carb which allowed it to run for a few seconds. They diagnosed it as a bad carburetor. So $600 later they replace the carburetor and still the generator will not start. While trying to prime the generator you can hear it click but no fuel was coming out. So I left there they told me I need to go see an onan certified generator repair shop, at home this morning I just on a whim tried it and the fuel pump will prime...I can hear it and see the hose filling. So I shut it off to try it again and the same problem there’s a click and no priming. Anybody ever had this before? Thanks for your time!

dougrainer

Carrolton, Texas

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Posted: 08/18/19 10:41am Link  |  Quote  |  Print  |  Notify Moderator

The most common problem with a 10 year or older Motorhome, is, the rubber fuel line from the Fuel tank pick up tube to the Genset has dry rotted. The small cracks cause air thru the rubber and that disables the fuel pump from getting its prime to pull fuel. A quick way to determine this is to connect a gallon gas can and remove the existing fuel line from the genset and connecting a good new rubber line and see if the Fuel pump then primes. Usually it will. Doug

PS, If you hear a click, that may be the fuel cut off solenoid opening. BUT, you should also hear the Fuel Pump rattling trying to pump. This would mean your above fuel line is good. Also, I believe the fuel pump has a pressure cut off. When the fuel pump cannot pump, its internal pressure switch shuts off. When testing the fuel prime you need to disconnect the metal line at the Carb input. Onan and other Genset makers require a LOW pressure fuel pump which is what Onan makes and supplies. The aftermarket Automotive similar looking pumps are 2 to 3 times the PSI of a genset pump.

Rsnawder

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Posted: 08/18/19 10:46am Link  |  Quote  |  Print  |  Notify Moderator

Thanks Doug...so the prime seems to be intermittent. It was just running for about 5
Minutes then stops. After it stops all I hear when I go to prime is a click...no fuel
Moving. If I wait about 10 minutes it’ll prime and start again, run for about 5 min then shut off. My fuel tank is between 1/4 and 1/2.

dougrainer

Carrolton, Texas

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Posted: 08/18/19 10:48am Link  |  Quote  |  Print  |  Notify Moderator

Rsnawder wrote:

Thanks Doug...so the prime seems to be intermittent. It was just running for about 5
Minutes then stops. After it stops all I hear when I go to prime is a click...no fuel
Moving. If I wait about 10 minutes it’ll prime and start again, run for about 5 min then shut off. My fuel tank is between 1/4 and 1/2.


Get the fuel tank above 1/2 tank and retest. Your 1/4 tank pick up may not be accurate. Doug

Rsnawder

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Posted: 08/18/19 11:29am Link  |  Quote  |  Print  |  Notify Moderator

Will do..then I’ll report back. Thank you

Rsnawder

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Posted: 08/18/19 12:44pm Link  |  Quote  |  Print  |  Notify Moderator

Filled to 3/4 tank, same results. I’m going to try 2 things:
1). Charge all batteries to fill then try again
2). Leave the gas cap off.

It’s a stretch...any other suggestions?

Thanks!

dougrainer

Carrolton, Texas

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Posted: 08/18/19 01:45pm Link  |  Quote  |  Print  |  Notify Moderator

Gas Gensets use about .7 gallons per hour. Connect a 1 gallon Gas can to the Gas input of the Genset and run the Genset. If it fails, then you need a new fuel pump. IF it stays running then think about a rotted supply line from the fuel tank. Doug

Matt_Colie

Southeast Michigan

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Posted: 08/18/19 04:16pm Link  |  Quote  |  Print  |  Notify Moderator

Rsnawder,

I know you may not think it is old, but 15 years (yours is supposed to be 14) is about the life of a fuel line these days. Make sure it is replaced with something alcohol compatible.

Matt


Matt & Mary Colie
A sailor, his bride and their black dogs going to see some dry places that have Geocaches in a coach made the year we married.


wa8yxm

Wherever I happen to park

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Posted: 08/18/19 04:37pm Link  |  Quote  |  Print  |  Notify Moderator

YOu say it primes and runs. then it stops and won't prime. then it primes and runs, then it stops and won't prime.

The fuel pickup in the tank has a strainer (pre-strainer) just like the water pump has. If you've left old gas in the tank (Gasser) or algae has grown (Diesel) that pre-strainer may be clogged.

Then there is the fuel filter it too can clog

And a pinched fuel line not letting fuel through.

all of those will act exactly as you have described Error code will show "No fuel".


Home is where I park it.
Kenwood TS-2000 housed in a 2005 Damon Intruder 377


turbojimmy

New Jersey

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Posted: 08/18/19 05:49pm Link  |  Quote  |  Print  |  Notify Moderator

I had a similar problem with my '84. Fuel pump would prime, generator would run for a while, fuel pump would start to clatter (as it ran out of fuel). Run times varied - it was frustrating.

Turns out it was a loose hose clamp at the fuel pickup at the tank. A dry rotted line would behave the same way.

Disconnect the fuel line and run it right from a gas can. If it runs without any trouble, there's your answer.


1984 Allegro M-31 (Dead Metal)



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