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Generator Troubleshooting
When I bought my LD the guy said the generator would start but would immediately quit so I factored that into my purchase price. On the two day drive home it started and ran fine so I thought big win here. I started it several times at home and it always worked but a few days ago when staying in a hot campground one afternoon I started it and it ran about ten seconds before it quit. Tried a few more times then put a new spark plug in and it still wouldn't start. I bought a new fuel filter on the way home and was going to try that but thought I'd give the generator another try when I got home. It fired right up and I ran it two hours with the AC on to put a load on it. Any ideas?
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Re: Finicky generator
Reply #1
Assuming you had at least 1/4 tank of gas at the time?  Sorry if that's the lamest question but years ago I caught myself in the same position and it was the gas tank level

Bill
2013 31' Silver Twin Bed
Semi-retired 6/21....

Re: Finicky generator
Reply #2
Assuming you had at least 1/4 tank of gas at the time?  Sorry if that's the lamest question but years ago I caught myself in the same position and it was the gas tank level

Bill
Tank was nearly full but good thought
Discuss anything with anyone and disagree agreeably. Always be polite and respectful.

 
Re: Finicky generator
Reply #3
Hi Sawyer. So how full was your gas tank. when it ran fine, versus when it didn't?  Your year of coach is probably in need of a new gasoline line from the tank to the generator.     RonB
RonB (Bostick) living in San Diego
Original owner of "Bluebelle" a '99 TKB

Re: Finicky generator
Reply #4
Hi Sawyer. So how full was your gas tank. when it ran fine, versus when it didn't?  Your year of coach is probably in need of a new gasoline line from the tank to the generator.     RonB
When generator wouldn't run tank was three quarters full. When I got home and generator ran fine tank was under half full. I've heard about gas line isues on these and if after I changed filter and fuel pump it still wouldn't run I'd look into that. I don't think that's it though or it wouldn't have run fine yesterday for two hours. I'm baffled on this and may change fuel filter just because.
Discuss anything with anyone and disagree agreeably. Always be polite and respectful.

Re: Finicky generator
Reply #5
Hi Sawyer, well you said 'hot ' campground, so on the Onan Emerald II there is a choke setting winter/summer. I could suspect that if the choke were set to winter it would start, but not continue to run. There are two spark plugs, since it is a two cylinder engine. The air cleaner could need changing. How many hours use does it have?  It will shut down if the oil pressure and level aren't right.  RonB

p.s. sounds like your fuel line and fuel filter are ok. They don't suddenly clean themselves.
RonB (Bostick) living in San Diego
Original owner of "Bluebelle" a '99 TKB

Re: Finicky generator
Reply #6
Hi Sawyer, well you said 'hot ' campground, so on the Onan Emerald II there is a choke setting winter/summer. I could suspect that if the choke were set to winter it would start, but not continue to run. There are two spark plugs, since it is a two cylinder engine. The air cleaner could need changing. How many hours use does it have?  It will shut down if the oil pressure and level aren't right.  RonB

p.s. sounds like your fuel line and fuel filter are ok. They don't suddenly clean themselves.
I put a new air filter on when I bought it as part of an oil change. Mines the 4k with only one cylinder at least I think. I only see one plug. Oil levels good but I didn't know about summer winter setting and that campground was very hot the afternoon we pulled in there. I'll look into that. That sounds like a possible reason.
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Re: Finicky generator
Reply #7
You may want to adjust for altitude if your generator has this feature as ours does. Originally it ran great at sea level but at higher altitude it tended to run a tad rough until I made this minor adjustment.
Here are a few pics of ours you can see the adjustment device clearly.

Hope this helps.

Kent
2015 27' RB "MissB.Haven"

Re: Finicky generator
Reply #8
Hi Sawyer. I guess that that choke I was referring to (winter/summer) is actually an air pre-heater. There is a choke in there also. I forgot that there is also an altitude adjustment, although I think it isn't so important unless you are over 5000 feet.
   The other spark plug is accessed from the back side. I have seen the hole but I've never worked on it.
   A trouble shooting guide           https://www.flightsystems.com/pdf/onan-rv-troubleshooting-guide.pdf             mentioned that a sticking oil level switch can cause intermittent problems similar to your problem. More of an issue if the oil had been sitting for a long time. Of course when you changed the oil, the switch could still be sticking because of earlier neglect.  RonB
RonB (Bostick) living in San Diego
Original owner of "Bluebelle" a '99 TKB

Re: Finicky generator
Reply #9
Several possibilities.                                                                                                                                                                                             
If the generator had not been run for an extended period, the carb could have been gummed up. Flowing fresh fuel through it could be cleaning it out.
A failing fuel pump can act up intermittently .                                                                                                                                              
21 year old fuel lines could still be the cause. I would closely inspect them.
                                                                                                                                                           
Your 1997 LD has a 4000-watt, two cylinder, Onan Emerald genset. It's a more durable generator than the later, single cylinder generators, with nearly twice the life, when cared for.

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

Re: Finicky generator
Reply #10
You have ruled out the usual reasons. It could be the generator fuel pump. That's what I thought of when you said it was hot weather. Starts and runs, then fails. It's a PIA to replace but there is an DIY article on The Companion for the single cylinder models. Maybe it's about the same for yours?
Don & Dorothy
Sold our LD in June of 2023

Our boring always non-PC travel blog
Traveling Dorothy

Re: Finicky generator
Reply #11
Thanks to everyone for all the suggestions and informing me my generator is two cylinder. I guess you have to drop it to get to the backside plug? I did fiddle with the altitude setting when it didn't run and my carb is set on summer so I think I can rule that out. It seemed like it wasn't getting gas when it started and then stopped and never started again so I'm thinking fuel pump is acting up intermittently as was suggested. I'll look into that with the link that was provided. Thanks again.
Discuss anything with anyone and disagree agreeably. Always be polite and respectful.

Re: Finicky generator
Reply #12
The fuel pump is easy to test. Run a small piece of clear fuel line from the pump to a gas can.
This teat also functions to check the fuel line from the tank to the generator.
I had problems and finally figured out the voltage regulator wasn't working correctly.
When it did not sense output voltage, the generator stopped. Took awhile to get there but there is great support for the Onan's on the web and we found diagnostic tests that confirmed the voltage regulator.
Jota
96 23.5 FL

Re: Finicky generator
Reply #13
Also, mine recently needed the fuel line to the generator replaced.
One of the symptoms leading up to the final failure was that it sometimes would run fine, under load for hours.
Only not to start up next time or when it was hot out.
Jota
96 23.5 FL

Re: Finicky generator
Reply #14
Also, mine recently needed the fuel line to the generator replaced.
One of the symptoms leading up to the final failure was that it sometimes would run fine, under load for hours.
Only not to start up next time or when it was hot out.
Well that's pretty interesting. From what I've read replacing that line is a major job involving dropping the fuel tank. Not looking forward to that if it's my problem and with the age of my LD it may well be.
Discuss anything with anyone and disagree agreeably. Always be polite and respectful.

Re: Finicky generator
Reply #15
The fuel pump is easy to test. Run a small piece of clear fuel line from the pump to a gas can.
This teat also functions to check the fuel line from the tank to the generator.
I had problems and finally figured out the voltage regulator wasn't working correctly.
When it did not sense output voltage, the generator stopped. Took awhile to get there but there is great support for the Onan's on the web and we found diagnostic tests that confirmed the voltage regulator.
When I bought my LD the guy said it needed a new regulator so possibly he was right and I didn't get a big win. Good grief this is getting complex.
Discuss anything with anyone and disagree agreeably. Always be polite and respectful.

Re: Finicky generator
Reply #16
You know I got by twenty plus years in my old slide in camper with no generator and I'm beginning to miss those days.
Discuss anything with anyone and disagree agreeably. Always be polite and respectful.

Re: Finicky generator
Reply #17
"From what I've read replacing that line is a major job involving dropping the fuel tank."

Look on the bright side! I'm on my 3rd fuel pump, both failures held me dead in the water. I've also had that little 2" pig-tail piece of fuel line replaced above the tank. So that's three times the tank had to be dropped. Two of those were unscheduled, the third was planned. Which way would you have it? Your fuel line and or pump will fail. Do it now and save some grief.  ;)  8)
Steve S.
Lazy Bones & Cedar
2004 30'IB (Island Bed)
Yesterday is History, Tomorrow is a Mystery
Live for the day!

Re: Finicky generator
Reply #18
"From what I've read replacing that line is a major job involving dropping the fuel tank."

Look on the bright side! I'm on my 3rd fuel pump, both failures held me dead in the water. I've also had that little 2" pig-tail piece of fuel line replaced above the tank. So that's three times the tank had to be dropped. Two of those were unscheduled, the third was planned. Which way would you have it? Your fuel line will fail. Do it now and save some grief.  ;)  8)
Im thinking a five gallon fuel tank on the roof with a line running down to the generator. No tank drop no fuel pump. I'd say LOL but I'm half serious.
Discuss anything with anyone and disagree agreeably. Always be polite and respectful.

Re: Finicky generator
Reply #19
"...a five gallon fuel tank on the roof..."

By the way, when the pig-tail was replaced I also asked to replace the plastic fuel line from the tank to the generator with stainless steel line. Cheap insurance!   :D
Steve S.
Lazy Bones & Cedar
2004 30'IB (Island Bed)
Yesterday is History, Tomorrow is a Mystery
Live for the day!

Re: Finicky generator
Reply #20
I have a 96 FL. The cost to have my line replaced was under $150.
I used a 5 gallon gas can for about 3 weeks waiting for an opening.
It works fine and I could calculate my consumption pretty easily.
Now I keep a short piece of clear fuel line in my tool kit. Hopefully to never need it again.
Voltage regulator was about $200 and easy enough to install, if that turns out to be the problem.
Jota
96 23.5 FL