• Onan 7500 Diesel Generator Troubleshooting
• Onan Generator 7500 Troubleshooting

I have an Onan 7500 QuietDiesel generator in my 2000 Itasca Horizon. It recently quit - starts and runs for 10-20 seconds.

Then gives an '1-1' error code. I have also found chunks of magnets in the lowere service door.

I am just about 100% sure that I have the famous problem with this generator - it sheds its magnets and destroys the generator stator and rotor. I am a real do-it yourself guy and plan on dropping the generator this weekend and fixing it myself. One local dealer has quoted $965 for the stator and $517 for the rotor - parts cost only. So a few questions for the community - has anyone out there done this already and do you know of a lower cost source for the parts? And does anyone out ther have a service manual I can buy or get a copy of? The part number for the manual is 981-0522 It is not the cost (it is about $30) it the fact that I contacted several dealers, and they are quoting me AT LEAST two weeks to get me the manual. I would like to get it fixed way before that.

Wayne, just did all mine a couple months ago. These are for the HDKAJ-H Use same oil as the Cat, 3 qts incl. Use same antifreeze also, app. I recommend ELC in both.

Cummins NW prices: Air filter $23.01 Fuel filter $25.98 Oil filter $14.86 Camping world was app. $5 more for whole order if they are closer to you. Replace your radiator cap also if you haven’t already. 130-4320, Cummins $9.10 Cummins now has a discount if you join their power club.

I think it’s another 10% off? I bought my Onan fuel, oil and air filters from the Filter Barn (online) at about the same prices that Maverick paid. Real Onan parts from a Cummins/Onan place aren't a whole lot more expensive, but local sales taxes add a bit more. I bought Onan filters at NAPA once, but they didn't have a cross-ref for one of them and I had to go to Cummins for that anyway, so didn't bother with NAPA again for Onan stuff.

Onan 7500 Diesel Generator Troubleshooting

It did not cost anywhere near $80 at NAPA, though. I usually get my Cummins oil and fuel filters from NAPA and bought a big diesel air filter there as well.

The $80 NAPA oil filter price I saw came from the invoice a friend paid a local RV repair shop. I saw the invoice and reacted immediately because we have the same engine, and I'd bought the OEM filter just the day before. Cummins offered me two filters; One was $24 and the other (that I bought) cost $32. I checked what filter they'd installed on our friend's coach and saw NAPA oil and fuel filters. I suspect the repair shop put a healthy markup on the filter, but I can't somehow reconcile 3X the Cummins price. Several years ago, a soon to be permanent customer of mine, had been clipped by a competitor over an alternator belt with installation on his aircraft.

Onan Generator 7500 Troubleshooting

The customer had been charged $150.00 for a belt and $100.00 for installing it on his aircraft because it was 'aircraft'. The customer still had problems with it a month later and appeared at my shop for a repair. To add 'insult to injury', it was the wrong belt and installed incorrectly. I installed the correct belt,($12.00) and adjusted it correctly,($30.00 labor) no more problems and I gained a permanent customer.Dan (Theres a moral there somewhere).