Every week we take a look back at the RV Doctor Gary Bunzer's answers to your tough questions. He has been providing insight into troubleshooting, repair and preventative RV maintenance since 1968.

Dear Gary, I have an Onan RV Marquis generator in my Airstream Land Yacht. The generator will start, but once the button is released, it shuts off. I’ve tried many things. I’ve checked the fuel filter and it was fine. I cleaned the spark plugs and they were okay. Can you offer any other suggestions? I am presently traveling in California and need to fix the problem ASAP. Thanks! — Barbara K.

Barbara, there are many reasons why the generator might shut down when the start/stop switch is released. Here's a quick list...

• In earlier gensets, a burned out resistor caused that symp­tom.
• However, since the evolution of electronics, it can now be caused by
  • A faulty oil pres­sure switch
  • A faulty voltage regulator
  • A failed control board
• The Onan Marquis requires sufficient oil pressure to keep running, so carefully check the oil level.
• If it is correct, then it may be a faulty oil pressure switch, or it could also be stuck in the open position.
• The generator also requires enough AC voltage to keep it rotating. A faulty board can reduce or eliminate that AC voltage supply.

Unfortunate­ly, it’s best for a certified RV technician to troubleshoot and diagnose most of these situations. They’re not really a do-it-yourself repair. But check the oil level first. That IS something you can do before contacting a reputable repair shop. You can also make sure all the plug-in contacts and wire connections are clean, dry and tight.

Hope this information helps and good luck!

All effort is made to ensure the correctness of Gary’s responses; however, not all responses will apply in every instance. Some situations may mandate a visual inspection and further hands-on testing. It is imperative that if you choose to follow any instructions or procedures outlined in The Doctor’s Orders column, you must first satisfy yourself thoroughly that neither personal nor product safety will be compromised or jeopardized. If you are in doubt or do not feel comfortable about a procedure, do not continue. Simply call your local RV service facility and make an appointment with them. Remember, the advice, recommendations and procedures offered by The RV Doctor are solely those of Gary. They do not necessarily reflect the opinions, procedures and recommendations of Lippert, this publication or any of its advertisers.