We own an older (1990s) motorhome with an Onan generator (gas). We are ready to go away in a couple of weeks, so I started to check everything. The generator is running fine but is not putting out power. There is a junction box right next to the generator where I opened it while it was running and no power was present there. Is there anything else I can check? The nearest Onan repair shop is 50 miles away! —Bill D.
If you cannot measure the generator voltage at that first junction box, chances are the output voltage is not even leaving the generator itself. Basically, everything on the coach is now isolated. Depending on the year of the generator, you might see two small, pop-out circuit breakers (see photo), on the side of the control box. Chances are they are in the popped out, or tripped, position. Try pushing them both in and see if you then have any voltage to the RV.
Be sure all loads inside the coach are turned off prior to resetting the breakers on the generator. If the integral generator breakers are not the issue, then there could be an internal problem in the generator, but I’d wager it’s the circuit breakers.
One caution! In the future, do not open any junction box or electrical panel while the generator is running or the shoreline cord is connected to shore power! Always disconnect or disable all 120-volt AC producing components before gaining access to any electrical connection.