Onan 5500 Generator Storage

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jves

Active member
Joined
Dec 8, 2013
Posts
38
The idea of "exercising" the genset once a month under moderate load to prevent
varnish buildup in the carburetor just rubs me the wrong way.
In my opinion, "exercising" just puts more (useless) wear on the generator and the loads such as
A/C or water heater, not to mention waste of energy.
My idea for storage is to drain the carburetor bowl of gasoline.
Any thoughts on this from the Forum collective knowledge base will be appreciated.
Many thanks....
 

Larry N.

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Joined
May 26, 2010
Posts
7,723
Location
Westminster, Colorado
If the carb were the only possible problem, I'd tend to agree with you. But the generator itself (not its engine) is vulnerable to moisture buildup and corrosion, so a major reason for that periodic exercise is to dry out the internals of the generator. There have been a number of other topics here about this subject, and a search can find more detailed information, should you be interested.
 

Willandgiselarv

Well-known member
Joined
Jul 20, 2015
Posts
230
Location
Fairfield, Ca
The stator or alternator is the part not just the carburetor..and when moisture gets to it and wires get rusted and the windings shorts out.
This actually happened to me and cost me a lot to have it replaced on my boat.
 

camp4fun

Member
Joined
Sep 21, 2017
Posts
7
We have ?winterized? engines before by shutting the fuel off and letting them run out, on some engines this doesn?t work to well as it lets the rubber gaskets dry out in the carburetor. We were told it is better to treat the fuel with a good stabilizer and leave it in the carburetor.    This may not be relevant to your engine.

  The best thing you can do for your generator is take it south for the winter and use it on a regular basis. :)
 

John From Detroit

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Joined
Apr 12, 2005
Posts
24,782
Location
Davison Michigan
The point of exercising is not varnish build up in the carb as many thing but electronics.

True story:  I once bought a small portable. It was not "Clean power" my APC UPS refused to pass it when it was new because, as it turned out, it had not been exercised.

Well. one full tank of fuel later.. The APC was Happy as the parts that help shape the waveform (Capicators) were up to spec.  Sitting on the shelf they had changed value.. This is a common issue with electronics thats sit around and the generator is not just electrical. it is also electronic .
 

darsben

Well-known member
Joined
May 30, 2018
Posts
2,190
Location
Central NY in summer beautiful Casa Grande AZ in w
jves said:
The idea of "exercising" the genset once a month under moderate load to prevent
varnish buildup in the carburetor just rubs me the wrong way.
In my opinion, "exercising" just puts more (useless) wear on the generator and the loads such as
A/C or water heater, not to mention waste of energy.
My idea for storage is to drain the carburetor bowl of gasoline.
Any thoughts on this from the Forum collective knowledge base will be appreciated.
Many thanks....

Well you can follow the manufacturers recommendation and exercise it OR do as you wish you may be okay  not exercising or you may be buying a new STATOR from Cummins for $1500 or other less expensive parts. I exercise but new motor homes sit for really long periods at the dealer with no ill effect.
So basically YOUR RIG,  YOUR MONEY, YOUR DECISION.
 

catblaster

Well-known member
Joined
Jan 11, 2010
Posts
2,701
Location
Kissimmee, Floriduh
  I have two Lincoln 200 amp welders that are scrap because they sat for too long. These welders are nothing more than a big generator and react to a lack of use the same way, after sitting in this florida humidity for a period of time the moisture gets under the insulation and corrodes the windings.  The windings swell and short each other out then burn thru to make a disconnected circuit.  A machine that worked fine several months/year ago will no longer generate current and the windings cost more to replace than it is worth.  On the plus side I have two great 4 cyl engines to put on something else.
 

jmorrison

Active member
Joined
Aug 4, 2015
Posts
27
There are storage instructions in the Onan service manual - you could check here or online for a copy and see what it says.
 

Bobtop46

Well-known member
Joined
Mar 11, 2011
Posts
735
Location
Dunnellon FL
I exercise my generator.  I went to the Tampa RV show and attended the Onan information session/class, given by Onan.  As, stated above the exercise is mostly for the electric side of the generator and somewhat for the engine side.  Exercising the unit as described in the manual will only add 6-8 hours of use per year.  10 years later you have 60-80 hours on the unit.  Wear and tear should not be a concern.  My unit is 11 years old and has 158 hours on the dial.
 
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