Tank boost pump for Onan Gen

[jaherbst]

2017 25WAB Factory authorized dropping the fuel station/generator fuel tank 2" due to filling issues. I am now having issues starting the generator due to prime. Suspect boost pump at fuel tank is week or inop.
Checked all lines and once Generator is running it is fine. Engine fuel pump is working fine. No surging etc. There appears to be a separate line for the engine fuel line and the boost fuel line. Can anyone verify this.
Has anyone else changed the boost pump attached to the bottom of tank themselves? How difficult was it? Worst part would be draining the fuel with the fuel station pump but residual fuel will remain due to stand pipe level. Thoughts?

Jack

[Goats]

The only lines for the gen are the fuel line and evap line. The fuel pump in the gen is the only thing that pumps for the gen.

[jaherbst]

I think there is a boost/prime at the tank which is 25' away if I am not mistaken or does the engine pump do the priming also?

Jack

[Goats]

The fuel pump in the gen is what primes it also.

[MOODMAN]

Originally Posted by jaherbst

2017 25WAB I am now having issues starting the generator due to prime. Suspect boost pump at fuel tank is week or inop.
Jack

The return evap line might be plugged. I assume this is a diesel, right?

[Wolverine 1945]

Originally Posted by jaherbst

I think there is a boost/prime at the tank which is 25' away if I am not mistaken or does the engine pump do the priming also?

Jack

Are you holding the Prime for 30 seconds ???

[jaherbst]

Originally Posted by Wolverine 1945

Are you holding the Prime for 30 seconds ???

Yes, on the remote start even up to 60 seconds after the light goes on. Still takes a second boost before start and even sometimes a third. Must have at least a half tank of fuel before boost light even works. Taking it in after Thanksgiving to trouble shoot at Lazy days. Possible bad boost pump.

Once it does start it runs fine.

Jack

[Wolverine 1945]

Just had our fuel pump replace last week,,, I had taken the line off the carb and tried to prime,,, I got nothing,,, so I knew it was the pump or filter !!!
We also had the carb replaced in the spring,,, lack of use I guess !!!
But after having the carb replaced I ran it every month,,, until last month when it would not start !!! Spent way more $$$ on this generator that it is worth !!!
It is no wonder the ONAN services centers are so busy !!!

[jaherbst]

Originally Posted by Wolverine 1945

Just had our fuel pump replace last week,,, I had taken the line off the carb and tried to prime,,, I got nothing,,, so I knew it was the pump or filter !!!
We also had the carb replaced in the spring,,, lack of use I guess !!!
But after having the carb replaced I ran it every month,,, until last month when it would not start !!! Spent way more $$$ on this generator that it is worth !!!
It is no wonder the ONAN services centers are so busy !!!

Sorry to hear that. I have had three Onan's and this is the first problem I have had. It is a long way to the Gen from the fuel tank. (25') and uphill. No problem when new a year ago when purchased. I think that lowering the tank and distance are contributing factors. Keeping the tank 1/2 to 3/4 full helps somewhat but who wants to lug around all the extra weight.

Jack

[Wolverine 1945]

Originally Posted by jaherbst

Sorry to hear that. I have had three Onan's and this is the first problem I have had. It is a long way to the Gen from the fuel tank. (25') and uphill. No problem when new a year ago when purchased. I think that lowering the tank and distance are contributing factors. Keeping the tank 1/2 to 3/4 full helps somewhat but who wants to lug around all the extra weight.

Jack

Ours is probably 8 to 10 feet from the tank !!!
We keep it as full as we can !!! With Sat-Bil Blue,,, and Seafoam !!!

Roger...

[lbrunning]

electric fuel pumps are designed to push fuel and should be mounted as close to the tank as possible not saying that you cant get by mounted farther away from the tank but the harder the pump has to work pulling fuel the shorter the lifespan of that pump. This is just another example of the rv industry doing things that will work most of the time instead of doing things correctly because of the time it would take to do it right.

[x90rider]

Is your fuel tank vented well? We have to loosen the fuel cap on our toyhauler when we run the Onan.

[jaherbst]

Originally Posted by x90rider

Is your fuel tank vented well? We have to loosen the fuel cap on our toyhauler when we run the Onan.

Something to consider. I will check. I think the pump is getting worn out due to long distance from tank to Onan. This causes extended boost time.

Jack

[Wolverine 1945]

I am guessing a pump should last longer than 2 & half years and 6 hours of run time,,,
when only drawing fuel from about 8 to 10 feet !!!
It is an ONAN fuel pump not a FR pump !!!
Carbs & Pumps are all a POC !!!

[lbrunning]

Yes wolverine I know they are onan parts but when you read the installation instructions on a electric fuel pump they state that they should be mounted as close to the fuel tank as possible and below the pickup line and it is the toy hauler or mh manufacturer that determines the location of the generator. I have also seen equipment and vehicles that a change from pulling fuel 8 to 10 feet to pushing fuel 8 to 10 feet resulted in better performance and longer life out of the fuel pump. Also not trying to ruffle any feathers here but a generator is not a piece of equipment you can ignore and expect to work 6 hours in 2.5 years today's gasoline be it ethanol or not has little shelf life and deteriorates and leaves deposits that can ruin your carburetor and fuel pump. Run your generator long and hard follow manufacturers maintenance recommendations and you will have better luck. I put over1500 hours on my first onan and currently have over 2000 hours on the one in my 2011 sunseeker and between the 2 have only replaced one fuel pump.