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Onan Generaor - 10 yr old

TC_Z
Explorer
Explorer
We have a Onan Marquis Gold 5500 watt generator. It is 10 yrs old. I service oil and air filter. We have never had a problem with it. It has 500 hrs run time. When it used to start it would crank then run smoothly almost immediately. Now when cranked it sort of putt, putt, putt, putt, putts, for 10-20 seconds then runs smoothly. Trying to decide if I should take MH in to get generator serviced. However not sure what they would do. Would they clean carburetor, or replace it? other? Or would they tell me it is 10 yrs old and I ought to buy a new one? Or is this the expected behavior when 10 yrs old and it is ok, this is normal, no service needed.

Wish I had more confidence in the service folks. Seems like when you have a MH they think money is not an issue for you. We are still making payments. What are your thoughts?
TC&Z
2007 Winn Voyage 38J, gas 8.1L engine
2018 Jeep Cherokee flat tow
22 REPLIES 22

TC_Z
Explorer
Explorer
Farmboy666 wrote:
It sounds like a fuel issue but 20 seconds really isn't an issue. Does it get fuel from main tank or it's own? Either way I would try some Seafoam first and that should help clean things up if it's fuel system.


Appreciate your suggestion. Our gen gets its fuel directly from the main MH tank. Unclear to me how you want me to introduce the Seafoam into the generator's fuel line. Please provide a bit more info how to do this, apologize its not obvious to me... thx
TC&Z
2007 Winn Voyage 38J, gas 8.1L engine
2018 Jeep Cherokee flat tow

centerline
Explorer
Explorer
TC&Z wrote:
We have a Onan Marquis Gold 5500 watt generator. It is 10 yrs old. I service oil and air filter. We have never had a problem with it. It has 500 hrs run time. When it used to start it would crank then run smoothly almost immediately. Now when cranked it sort of putt, putt, putt, putt, putts, for 10-20 seconds then runs smoothly. Trying to decide if I should take MH in to get generator serviced. However not sure what they would do. Would they clean carburetor, or replace it? other? Or would they tell me it is 10 yrs old and I ought to buy a new one? Or is this the expected behavior when 10 yrs old and it is ok, this is normal, no service needed.

Wish I had more confidence in the service folks. Seems like when you have a MH they think money is not an issue for you. We are still making payments. What are your thoughts?


ALWAYS, unless you have fuel leaking or a complete blockage, run some seafoam thru the system before taking it for repair.... in nearly every case where the motor has ran fine, and then sat for a spell, and now it doesnt run as good, the seafoam will dissolve the gum and varnish that is causing the problem... and it usually only takes 4-5 hours to do its thing...

one can always drop 200-500 dollars at the mechanic shop later, but if the problem can be solved right now with the purchase of an $8 can of seafoam, its a better way to go, in my opinion...
2007 M-3705 SLC weekend warrior, 5th wheel
2014 Ram 3500 CC/LB, 6.7 Cummins
2004 Polaris Sportsman 700
2005 Polaris Sportsman 500 HO
1979 Bayliner 2556 FB Convertible Cruiser
Heavy Equipment Repair & Specialty Welding...

ksg5000
Explorer
Explorer
Any small engine repair guy should be able to fix - did that once when on the road. Normally I take my generator issues to Truck dealers - any of the refrigerated trucks use generators to run the refers and they are well suited to handle generator issues. I would never take generator issue to RV dealer and Onan/Cumming dealers are expensive and often backlogged.
Kevin

gbopp
Explorer
Explorer
You service the oil and air filter. Do you change the generator fuel filter?
If someone tells you it needs to be replaced because it's 10 years old. Don't walk, run away.

I have a 1996 Southwind with the original Onan 5000 generator. It woeks great.
I agree with running some Seafoam through the fuel system.

Robocop
Explorer
Explorer
I am not a rocket scientist and always follow a good post. Although only 7 years in my MH, I have noticed a similar situation. I do the routine maintenance, have similar usage hours and exercise it on a load 2 hours a month. I am of the belief that the start up lag, more noticeable in colder temps of course, is about priming and then fresh gas getting through. Once it kicks in, runs smoothly.
Scott

2011 Sunseeker 3170DSF
2002 Honda CR-V toad

"Courage is the thing. All goes if courage goes."
"Do not mistake my benevolence for weakness."

Dale_Traveling
Explorer II
Explorer II
If you determined to have someone look at it call around to the small engine service places rather than the local RV dealer. All they do is small engines day in and day out. Just because it's bolted to an RV doesn't mean it's something strange or exotic that needs a RV guy to look at it.

Although run time is low it might need a bit more maintenance at this point in it's life then oil and air filter replacement. Finding a local small engine tech who will assist can make life a little easier. Don't forget the mobile mechanics either.
2006 Hurricane 31D built on a 2006 Ford F53

DrewE
Explorer
Explorer
I rather doubt it's the carburetor since it's running well once it gets going. This sounds to me more like an initial fuel supply problem, either insufficient priming (often done by holding the control switch on stop for fifteen seconds or so before starting, though I don't know about this particular model) or a fuel pump that's getting weak or maybe a pinhole or not quite tight fitting in the generator fuel line allowing air in and fuel to drain back to the tank between uses.

It's possible that the choke linkage could be a bit sticky or need some adjustment, too.

Any of these should be pretty straightforward for a competent shop to figure out and fix, depending somewhat on ease of access. If they tell you to get a new generator, go elsewhere; that's crazy talk.

Especially as this is new behavior, I wouldn't call it exactly normal or proper, but it doesn't sound especially troublesome to me either, so long as it doesn't get too much worse and has trouble starting when you need it.

If you ask about things in the Tech Issues forum, you'll likely get better answers from people who (unlike me) have a very thorough knowledge of these generators.

Farmboy666
Explorer
Explorer
It sounds like a fuel issue but 20 seconds really isn't an issue. Does it get fuel from main tank or it's own? Either way I would try some Seafoam first and that should help clean things up if it's fuel system.