Much like humans, generators don’t like being couch potatoes. Just like our arteries clog up from a sedentary lifestyle, so does bad fuel gum up tiny passages in carburetors when left to stagnate. Most RV generators die from neglect, not old age.

How Often Should I Exercise My RV Generator?

All the major RV genset manufacturers, such as Onan and Generac, recommend exercising your onboard generator at least once a month for 1-2 hours at 50% load. (Details vary – see your Owner’s Manual). This lubricates the engine organs, displaces any moisture buildup, mixes the engine oil, and consumes old fuel.

Exercise isn’t just good for the moving parts within the engine; the generator itself (the rotor and stator portion) benefits from occasional exercise as well, since the heat and airflow dry out the windings and flex the drive belt (if equipped) to prevent dry rot. Plus, the rotor shaft bearings don’t like sitting for months at a time any more than you like being bedridden. 

What Kills RV Generators?

When I am called to work on a generator, the root cause is rarely over-use. Normally, the issues are from neglect and abandonment: clogged carburetors, soiled fuel filters, shorted windings, etc. These are not always easy issues to fix. Some carburetors are difficult to thoroughly clean without a long bath in an ultrasonic cleaner and a whole lot of scrubbing with Lilliputian wires and brushes. And if you are unlucky enough to have a shorted electrical winding, that usually demands a full replacement of the rotor or stator, which will quickly reach into the four figures.

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You can avoid expensive repair bills by giving your generator the TLC it needs. Exercise it monthly! After a suitable warmup period (usually 2-5 minutes), put the generator under load (e.g., air conditioner or space heater) for 1-2 hours. Then disconnect the load and let the generator run at no-load condition for 5-10 minutes to cool down. 

Putting Your RV Generator Into Storage

If you’re putting your RV into long-term winter storage, use a fuel stabilizer in your gas tank. Pure gasoline will degrade in 3-6 months. Or you can run the generator dry. That’s right – just let it run until it all the fuel is gone. (If you have a full gas tank and don’t want to waste the fuel, you can temporarily disconnect a fuel line). This is particularly useful if you use gasoline with ethanol (like E10 or E20), which leaves a lot of varnish behind when it degrades. This varnish clogs up tiny fuel and air passes in a carburetor, many of which are too small for even a paperclip to pass through! 

If you put your generator into long-term storage and forget about it for 6 months out of the year, I would definitely run it dry, and I would use pure gasoline (often sold for boat/marine use at gas stations) for the last fill-up. Store the RV somewhere where temperature and humidity are moderate and consistent, and your generator will thank you.