Onan Generator 1000 hour service

I THINK MINE IS A 7500 AND HAS 3500+ HOURS ON IT AND THE ONLY THING THATS EVER BEEN DONE TO IT IS OIL & FILTER EVERY YEAR.......DIDN'T MEAN TO USE CAPS

Its your call. I know some folks talk about going many more hours without doing anything other than fluids and filters.

I had a 2002 Journey with the 7.5KW Onan diesel generator. At 10 years of age and about 1,200 hours, I decided to do the full service. I used a motorcycle jack to drop the generator out from under the coach. It was not that hard to do.

I replaced all the hoses, had the radiator cleaned and checked, changed thermostat, drive belt, temp sensor and did a valve adjustment. I believe in preventative maintenance.

If you have to pay a shop to do it all, it will be expensive. However, if you get another 8 - 10 years of use before having to do it again, that may cost you less than what you would spend modifying your coach.

I'd vote for fluids and filters each year. The only need to remove the unit is for thermostat, water pump, and on some a fan belt.
I did the remove and replace by myself and it was time consuming but not difficult. The temp sensor went bad which shuts the unit off after a few minutes, so it had to come out.
There's not a great deal holding these units in place, fuel, electric out (120v). Electric controls, and a few nuts and bolts. Using a floor jack and 2 furniture dollies, and some blocks of wood not a big deal.
Let me know if you need more info.

Might ask around at a couple salvage yards and find the front end with rollers and be close to a bolt up. Then again for a 1000 hours at a time bolting in rather than roll out might be more in economic line.

LEN

Everybody is responding about the mechanical maintenance. What about maintenance on the electrical end? Such as the generator slip rings, brushes, rotor, stator, cleanliness. Is it full of dust (dirt)?

All of the dust and grime that accumulates can break down the insulation on the electrical parts and the resistance of the insulation to ground drops. After 1000 hours of service there is more to look after than lube, oil, spark plugs, hoses, etc.
Removing the generator will be cheap compared to a new rotor and / or stator or the possibility of another generator (used) that will then need to be PMed before installation. Bite the bullet and do it. Remember the oil filter add years ago, "Pay Me now Or pay me later".
This is the same thing.

The 7500/8000 Onan quiet diesels do not use brushes nor have a rear rotor shaft bearing (they use a permanent magnet rotor with an inverter to produce a.c. power) so that is one less worry for maintenance. But the fan belt is usually only good for 1500 hrs or so. Owners of the 10 and 12 kw units need to service the brushes and slip rings, plus rotor bearing at 3000 hrs or so. If bearing fails and spins in end frame, you may be looking at $2000 plus in parts plus labor for a $25 bearing failure. The Kubota engines are tough as nails, but scheduled oil and coolant maintenance keeps them running practically forever.
All these units use same coolant temp. sensor, and are often problematic. We always change the sensor at our shop when gen is out of coach. They are not very expensive. Water pumps usually last 5000+ hours, but most folks with motor homes in recreational use seldom put this many hours on them. It would be nice if motor home manufacturers would put all gensets on slideout frames, but they tend to not spend money where not necessary