Thread Tools Display Modes
Old 01-23-2016, 09:06 PM   #1
Senior Member
MNtraveler's Avatar
Join Date: Oct 2015
Posts: 1,735
Exercising the generator

Good article by a man who knows generators.

Key points: minimum 2 hrs./month (good to remember even when always or generally plugged in...and in the winter even if batteries out); and minimum 1/2 load.

RV DIY Article – Why & How To Exercise RV Generators | RV DIY® Channel with Mark Polk

Land of 10,000 Lakes
2016 Forester MBS 2401R

2016 Forester 2401R
MNtraveler is offline   Reply With Quote
Old 01-23-2016, 09:24 PM   #2
Senior Member
Join Date: Oct 2014
Location: Central Florida
Posts: 445
I have a Guardian house generator that exercises every week on the time and day that I set it and it runs for twelve minutes not under load and that's the way It's set up at the factory.I run my rv gen about once a month for about 20 minutes, sometimes under load and sometimes not. I keep my MH in a storage yard and I'm not going to sit there for 2 hours, seems like a waste of time and gas.

poppytoymaker is offline   Reply With Quote
Old 01-23-2016, 11:14 PM   #3
Senior Member
Too Tall's Avatar
Join Date: Mar 2014
Posts: 821
I agree, 2 hours a month is a waste of time, fuel and engine. Overkill.
Rockwood 2104S, 2014 Ram 2500 Diesel.
USMC 68 -70
Too Tall is offline   Reply With Quote
Old 01-24-2016, 02:00 AM   #4
Senior Member
Join Date: Oct 2015
Posts: 1,421
That is a bit overkill. I fire mine up for about 30 minutes every 2 months under a small load.

I don't worry about bad fuel. A double dose of Stabil is all it needs to be ok for a year. I have 10 month old fuel in my snowmobiles and they ran just fine last weekend on our first trip out.

The reaal reason to run a generator is to avoid losing the "field" My parents learned this the hard way during a bad storm when their backup generator started, ran fine, but didn't generate any electricity. Good thing dad was sharp enough and knew how to flash the field using a cordless drill attached a corded drill that was plugged into the generator 120v outlet.

I do not know if loss of field excitation is an issue with inverter generators...not sure I'm not smart enough to know.

Regardless 30 minutes every couple of months is all that I ever do and I never had had a generator problem yet.
Skyliner is offline   Reply With Quote
Old 01-24-2016, 02:22 AM   #5
Senior Member
Join Date: Nov 2014
Location: Alberta
Posts: 137
yes, loss of the field coil magnet's magnetism is a big issue, but so is general corrosion of the entire armature if it sits in a high moisture area for extended periods. the engine itself isnt going to fair too bad if its got stabilizer in the fuel.

just running the generator from time to time is better than nothing, but it is always best to run it under at least 50% load to allow the engine and the armature to achieve operating temperatures.

The old trick of backfeeding power into the genset (usually via driving an electric motor with another power source) is only viable on most conventional generators. this wouldnt work on an inverter generator, but that being said inverter generators arent as susceptible to losing magnetism as a conventional generator. on the old engine driven welders that sat for a while we used to have to pull out the booster cables and give the field coil a zap to get it going lol

Either way, i would recommend running a genset AT LEAST every 6 months (in a moderate climate, more often in a humid environment) or any other engine for that matter.... Engines and attachments were designed to be used, let them sit and gaskets, seals, and bearings will all suffer.
'14 XLR 395AMP
'16 Ram 3500 DRW, 6.7 cummins w/aisin trans and 4.10 gears
ykdave is offline   Reply With Quote
Old 01-24-2016, 04:08 PM   #6
Senior Member
MNtraveler's Avatar
Join Date: Oct 2015
Posts: 1,735
Exercising the generator

Obviously people will do whatever they want. But here it is directly from Cummins Onan:


Exercising Your Generator

It may seem surprising that “not” using a machine could cause performance problems, but with RV generators that’s exactly the case. Regular “exercise” is an important part of keeping your generator healthy. Lack of exercise can cause moisture build-up and fuel system degradation that make it run poorly. In fact, in as little as 30 days, the fuel in gasoline-powered generators can begin to gum and varnish the fuel system. Fuel varnishing results in hard starting and surging. (A surging generator never settles at a stable operating speed.)

To prevent such problems, it is recommended to run gasoline generators at a minimum of 50 percent capacity (2000-watts, or one air conditioner for a 4000-watt set) for two hours once every four weeks. This is necessary to help keep moving parts lubricated, expel moisture and control fuel varnishing in the carburetor. A long two-hour exercise period is preferable to several short periods. While traveling, this can be accomplished by running the air conditioning. If you own a diesel generator, regular exercising can help reduce internal condensation and helps keep seals lubricated.


The cost for a 3.6K LPG unit for 2 hrs. @ 1/2 load is about 1.2 gal. @ $2.85 or about $3.40. For a 4K gas unit, 2 hrs. @ 1/2 load takes 1 gal. @ $1.65. Based on Cummins Onan average consumption figures and current local prices.

Land of 10,000 Lakes
2016 Forester MBS 2401R
2016 Forester 2401R
MNtraveler is offline   Reply With Quote
Old 01-29-2016, 07:15 AM   #7
Join Date: Feb 2015
Location: Carlisle PA
Posts: 69
In commercial applications such as phone companiy facilities and water authorities they automatically exercise their generators under full load weekly or bi-weekly. The reason: They require reliability.

Some of those Onan carbs can't be rebuilt so I figure I can burn a lot of gas before I match the price of a new carb.
2007 Chevy Couchman Freeloader
klspahr is offline   Reply With Quote
Old 01-29-2016, 07:37 AM   #8
Senior Member
DocsDad's Avatar
Join Date: Sep 2014
Location: SW Michigan
Posts: 230
I run mine about 30 mins per month. It's very cold in Michigan so the only thing I can think of loading it with is a space heater although I haven't done that yet. It's stored in the driveway until spring.
2016 Forest River Sunseeker 3100SS
DocsDad is offline   Reply With Quote
Old 01-29-2016, 07:39 AM   #9
Senior Member
Join Date: Dec 2012
Location: Windsor, Ontario, Canada
Posts: 642
I drain the carb of gas in my 3 gennys after I fog them. I haven't had a problem yet,(knocking on my head). I have an Onan and 2 hondas.
Pipeman is offline   Reply With Quote
Old 01-29-2016, 08:04 AM   #10
Senior Member
Join Date: Jul 2013
Posts: 320
I had my carb modified to run on propane as well as gas. Runs much better, spark plug lasts forever, oil does not get as dirty and no bad gas to deal with. One 20 lb propane tank is roughly equal to 5 gallons of gas.

Les & Heidi Kramer
2010 GMC Sierra SLE & 2014 Shamrock 23IKSS
Cleveland, OH
cpd1343 is offline   Reply With Quote


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

» Featured Campgrounds

Reviews provided by is not in any way associated with Forest River, Inc. or its associated RV manufacturing divisions.

Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -5. The time now is 11:45 AM.