Log In | Register
Skip to main content
Topic: Replacing the Generator Fuel Pump (Read 700 times) previous topic - next topic
0 Members and 1 Guest are viewing this topic.
Replacing the Generator Fuel Pump
The long saga with my generator refusing to run longer than a few minutes is finally resolved. 

How the generator got in this condition is worth reviewing.

Since we have owned our LD, we have been on the road over half of each year so the generator was used as we eschew campgrounds with hookups. However, camping wo popcorn is way too primitive. [It’s not the hookups, we mind, it’s that the people that frequent these CG’s are just not “our people”. We have little in common with them. Concrete Campers and Boondockers are two different species]

At home, I run the generator with a load for 45-60 minutes a month.
Using the generator, keeps the gasoline in the carburetor from turning to varnish and gumming it up.
A health issue prevented me from doing the monthly exercise for well over six months.
In hindsight, had I thought about it I could have drained the carburetor. But that bypasses the other reason for exercising the generator.

Not using the generator is true for most LD’s. I suspect few do a monthly exercise. (*) So there should be a lot of gummed up carbs out there. Mine sure was after months without use.


Symtoms:
It would run for 3-4 minutes, constantly surging. I could see the butterfly valves rapidly swinging back and forth. It would throw a 3-3 code which is not a documented code.

Trying to figure out the problem, I entertained all sorts of suggested remedies. Few had any bearing on the issue. One was to drain some oil out of the crankcase. Really! I noted the fuel pump supplied seemingly copious quantities of gas. After cleaning the carb bowl of varnish (https://www.youtube.com/watch?v=6053Qti0OLU&t=1102s) it ran a few minutes longer. I finally bit the bullet and ordered a Onan (not a knock off) fuel filter and pump. ($200+) I then embarked on the extremely PIA procedure to replace them. (https://www.youtube.com/watch?v=jlrHl0OWSZU)

Worth doing:
1)  Put colored tape on the wires you disconnect so you know where they go.
2) Take pictures before you take it apart.
3) Try see where the wires will have to be tucked back in as you carefully and slowly remove the control board. I failed this.

When I got it put back together, I primed it and it fired up and ran perfectly. Bob’s your uncle.

Be sure and tighten the fuel supply line from the pump before replacing the control board. I failed this and got to remove the board to access the fuel line. Also check for any other fuel leaks.



* If you see an aged RV advertised with low hours on the generator, figure it does not work. A 10 year old LD, should show 120 hours minimum on the meter.
Don & Dorothy
Sold our LD in June of 2023

Our boring always non-PC travel blog
Traveling Dorothy
Re: Replacing the Generator Fuel Pump
Reply #1 –
Not sure if it matters in this case, but my Onan manual recommends exercising the generator for two hours every month. Good to hear you got it working.
Greg & Victoria
2017 Mid-Bath  “Nocona” towing a manual 2015 Forester
Previously a 1985 TK
SKP #61264
Re: Replacing the Generator Fuel Pump
Reply #2 –
If one is good, two may be better. It should be under load, AC or 1,500 space heater.
Don & Dorothy
Sold our LD in June of 2023

Our boring always non-PC travel blog
Traveling Dorothy
Re: Replacing the Generator Fuel Pump
Reply #3 –
Don,  that was an excellent description of the way to resolve the carb problem. Yes, it’s a lot of work but more than worth it. Whoever is fortunate enough to get KoKo will have a very good motorhome that will last for many years to come.
2026 Coach House 27' "Casa Azul"
2010 RB "Monty"  &  2021 RB "Villa Verde"
2004 Born Free 26'
1998 Beaver Patriot 33'
1992 Barth Breakaway 28'
1982 Fleetwood Jamboree 23
Re: Replacing the Generator Fuel Pump
Reply #4 –
Quote from: HiLola  - 
Not sure if it matters in this case, but my Onan manual recommends exercising the generator for two hours every month. Good to hear you got it working.

Onan's recommendation of two hours covers all climates, including arctic conditions. In summer conditions, a half hour is enough, make sure to use as much power as possible to quicken the warm-up. Running the generator under load regularly does several good things besides keeping the carburetor full of fresh fuel.

Chimicum
Larry
Larry
2003 23.5' Front Lounge, since new.  Previously 1983 22' Front Lounge.
Tow vehicles  2020 Jeep Wrangler Rubicon, 2001 Jeep Cherokee
Photo Collection: Lazy Daze