sputtering difficult to run Onan (suspect a breather hose? if there is such a thing?)

[myla296]

We have an Onan 5500 that will start, but sort of sputters and may stay started, but may also shut down after a couple of minutes or so. We are starting to suspect that there must be a kinked breather hose. The reason why we say that is because we emptied a lot of gas from the tank (we have a toy hauler so we have a pump for the toys...but we don't want it to go bad so emptied it into our jeep)...anyway..and we heard a large metal noise that sounded like the tank pressure adjusting. We opened the gas inlet and you could hear the air movement (ghostly whisper is best comparison, LOL). So...we are suspecting that our generator is having trouble overcoming the pressure. We had to go so we didn't test it but I suppose we could leave the gas cap on the inlet loose, and try running the generator.

Question: Is it possible that there is a breather hose that is kinked? (I did try searching, but hope someone reading this knows the answer, and where it runs if a yes). Thanks in advance for any help!

 

[HornedToad]

Mine started sputtering and a new fuel filter solved the problem

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[myla296]

Mine started sputtering and a new fuel filter solved the problem

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Thanks, we did that one..so, maybe the fuel pump is next? (and so no, there's no breather hose that allows the pressure to be released? Thanks!)

 

[MTPockets]

Gasoline engines if unused for long enough period, can varnish in the tiny ports, unless you use something like StaBil in the tank. I've had portable gens do that and had to clean the carb.

 

[HornedToad]

Thanks, we did that one..so, maybe the fuel pump is next? (and so no, there's no breather hose that allows the pressure to be released? Thanks!)

On the EVAP models there is a return line see pages 31 to 37...

https://www.norwall.com/product_pdfs/6023_hgjaa_spec_j_install_2015.pdf



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[myla296]

Gasoline engines if unused for long enough period, can varnish in the tiny ports, unless you use something like StaBil in the tank. I've had portable gens do that and had to clean the carb.

Ugh!! Carbs! I'm avoiding that since I have run the engine just fine at one point since it did sit. But, it is on the waiting list.

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On the EVAP models there is a return line see pages 31 to 37...

https://www.norwall.com/product_pdfs/6023_hgjaa_spec_j_install_2015.pdf



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Wow, that is going to be VERY helpful, thanks...I'll take a look at the lines (it says that the return should follow the fuel . This will likely help in the future for other stuff too!

 

[porthole]

On the EVAP models there is a return line see pages 31 to 37...

https://www.norwall.com/product_pdfs/6023_hgjaa_spec_j_install_2015.pdf

Isn't EVAP for fuel injected only?

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We have an Onan 5500 that will start, but sort of sputters and may stay started, but may also shut down after a couple of minutes or so. We are starting to suspect that there must be a kinked breather hose.

Are you referring to a breather hose such as a vent for the tank?

Doesn't have one. The fuel system is sealed.

we emptied a lot of gas from the tank (we have a toy hauler so we have a pump for the toys...but we don't want it to go bad so emptied it into our jeep)...anyway..and we heard a large metal noise that sounded like the tank pressure adjusting. We opened the gas inlet and you could hear the air movement (ghostly whisper is best comparison, LOL). So...we are suspecting that our generator is having trouble overcoming the pressure. We had to go so we didn't test it but I suppose we could leave the gas cap on the inlet loose, and try running the generator.

I'm guessing by this you mean you used the fuel pump and fuel nozzle to dispense the gasoline from the trailer.
The noise you heard is indeed the tank walls flexing and is normal, as is the rush of air when you open the fuel cap.
The cap is vented one way - in - and it is a very small vent. Sufficient for the fuel flow of the generator running (1 gallon per hour) but not sufficient for running the fuel nozzle.

I wouldn't suggest rolleyes cracking the cap when running the nozzle.
The above is a "do as I say and not as I do"

And, use the ground-bonding alligator clip.

As for your running problems, see the link for Onan in my signature.

 

[myla296]

And, use the ground-bonding alligator clip.

Thank you! I know now not to chase a breather problem...but am wondering about the ground-bonding alligator clip? Sounds like a hazing joke.

Other than that, I will peruse your Onan link from your signature, thanks!!!

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As for your running problems, see the link for Onan in my signature.

"One of the steps for code 36 is replacing the fuel control solenoid, you can't buy one so I did the next best thing - rapped it with a wrench several times. Runs smooth as butter now. Ran good for 2 days and acted up on the last day. Rapped the solenoid once again and it ran smooth."

Guess I'll get my hammer ready!

 

[HornedToad]

Isn't EVAP for fuel injected only?


I'm definetly no mechanic so I tried to limit my advice to a copy of the installation manual... the only reason I know anything about these fuel lines is that I bought a new Onan 5500 off eBay in 2012 and found out I got such a good deal because it pre dated the New EPA Emissions Requirements starting in January 2011 for fuel system evaporator compliance (EVAP) and only had a fuel supply inlet. It took me forever to figure out I didn't need to or have a hook up for the extra vapor line in the 2013 model generator prep and could just cap off this extra hose with a sheet metal screw. Now if you look at the diagram on the EFI models, which also have to meet the 2011 EPA requirements, there is a third return line.

My politically correct answer to the OPs question about lines to/from the fuel tank was to post the diagram since a kinked hose was suspect.


My politically incorrect answer... Yea, thanks to the tree huggers there are a lot of lines!

 

[porthole]

...but am wondering about the ground-bonding alligator clip? Sounds like a hazing joke.

Inyourfuelstationcompartment,nexttothefuelpump

In your fuel station compartment, next to the fuel pump, there should be a coil of bare wire attached to the frame and terminating with a large alligator clip.

It's purpose is to connect to the item you are fueling to minimize the potential for static electricity discharge 'sparks' between the nozzle and fueled item. AKA 'Grounding', although you are not really 'grounding' anything, rather you are bonding the two vehicles together.

 

[myla296]

It took me forever to figure out I didn't need to or have a hook up for the extra vapor line in the 2013 model generator prep and could just cap off this extra hose with a sheet metal screw. Now if you look at the diagram on the EFI models, which also have to meet the 2011 EPA requirements, there is a third return line.

Well, it is a 2010 model so, I'm not running into EPA requirements.

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In your fuel station compartment, next to the fuel pump, there should be a coil of bare wire attached to the frame and terminating with a large alligator clip.

Thanks! Did not know about that...luckily have not created a fireball out of the place despite this fact.