Thursday, September 29, 2022


For good health, exercise … your generator!

Base image courtesy Travelers in the Middle East Archive (TIMEA) on wikimedia commons.

Courtesy of Onan Generators

Do diesel generators need exercising like gasoline generators?

Yes, regular exercise helps lubricate the seals and engine components and keeps carbon from building up. Regular exercise also heats up the generator windings and removes or expels excess moisture. In sets equipped with brushes, exercising helps prevent corrosion build up on the slip rings.

How often should I run my gasoline generator to keep it in good condition?

It may seem strange 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 use can cause moisture build-up and fuel system damage that makes it run poorly. In fact, in as little as 30 days, the fuel in gasoline-powered generators can begin to break down into gums and varnishes that clog 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, we recommend running gasoline generators at a minimum of 50 percent capacity (for example, 2000-watts, or one air conditioner for a 4000-watt set) for two hours at least once every four weeks. A long two-hour exercise period is preferable to several short periods.



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11 months ago

Can anyone tell me why I can’t start my Onan 7.0 kw genset? It ran perfectly, then I replaced the cracked rubber fuel line from the metal fuel tank line to the fuel pump and/or fuel solenoid. (About 10″ long). Now it will not start! (Gasoline unit and there is no fuel in the carburetor bowl. Thanks.

11 months ago
Reply to  DW/ND

I had a similar problem and found the fuel filter at the fuel pump was clogged as well as the fuel pump itself was going out. I replaced both for a small price and problems resolved. Good luck.

11 months ago

No one ever talks about propane generators.
Do they need exercising like gas & diesel?
How do you drain a propane carburetor?

11 months ago
Reply to  Harry

You don’t drain a propane carburetor, there is nothing to drain. I have one that I used to use regularly in my Plumbing Van but since I retired it stays idle, in fact after 3 years of non use it started up on second pull when I needed it. I will never purchase a gasoline generator again.

David Telenko
11 months ago

I must have missed something as the article states “Learn more about the best care for diesel and gas generators. Never mentions anything about diesel generators! I’m sure that have similarities but it would have been nice to actually include them in your article!

Dr. Michael
11 months ago
Reply to  David Telenko

I thought the exact same thing.
This article was shorter than the usual article. I wonder if some information was deleted?

11 months ago
Reply to  David Telenko

I agree with your comment and Thank you. We were told to run our Deisel Generator up to 30 minutes but not less than 20 minutes ONCE A MONTH with a LOAD. OUR A/C in the main room does the job.

Gene Meiser
2 years ago

I cannot get my Onan 4000 generator on my 1998 24′ Class C to start. I just had it repaired and serviced a few weeks ago and have run it a couple times since. (I am a part time RV’er). I just filled the gas tank, and it turns over but doesn’t start.
Any easy suggestions? Thank you!

11 months ago
Reply to  Gene Meiser

If they did not replace the fuel pump and filter, do so. That solved my problem

2 years ago

I have never exercised a generator in 30 years and never had a problem. Run it dry or drain the carb and you are good to go. Also if they are not used much use good synthetic oil and you dont need to change it. Oil doesn’t go bad inside the genset when not used.

2 years ago

I always use ethanol free fuel. I still add stabilizer and shut down the fuel and let the carb empty. No problems in over 20 years with this method in all of my small engines.

Bob Weinfurt
2 years ago
Reply to  Bob

I’m a retired mechanic. Using ethanol-free fuel is a big plus, running the carb dry is too. But I’ve found some gasoline stabilizers can cause problems, especially with pre-mix, carbureted 2 cycle engines.

Dr. Michael
11 months ago
Reply to  Bob

I have always used ethanol-free fuel in my lawn equipment.

2 years ago

When storing my generator after use I drain the gas tank then run it till it runs out of gas draining the carburetor bowl and gasoline from the gas tank. Been doing this for 40 years without any issues about the generator not running properly. Another tip once a year even if you didn’t use it much or at all change the oil in it.

2 years ago

Suggest adding stabilizer to ur gas generator fuel tank – keeps moisture out and does not allow fuel to break down. Do not understand why this “😍cheap” option not noted in article.

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