Generator maintenance! To start with, good luck. Roadtrek, at least in my 1994, mounted the generator so that it is impossible to service. The access door is barely the size of the internal Onan access door. The spark plug access is completely blocked and you might be able to replace the fuel filter if you are lucky. II think someone cut a piece off the lower hose, so I was unable to put in the new filter.
I decided to pull the whole think out and replace the plug, filter and all fuel lines. How to get it out? Disconnect all electricity and battery cables. Take the wooden covers off everything on the drivers side rear. take the cover off the auto changeover box and disconnect black, white, and green wires. Pull them back through to the generator compartment. Disconnect the +12 wire and pull it back through ( you may have to cut off the connector). Disconnect the remote control connector and the fuel line.
Under the coach, remove the muffler, and four bolts that hold the genset down. Here is where you find out that the genset will not move. By the way it weighs 113 pounds. I pried and pried and it would not move. Finally, looking at the oil drain, I could see a lot of sealant and started picking at it, getting out as much as possible. I then reasoned that they has sealed the whole bottom to the coach. Get a hydraulic jack and some cribbing. Jack slowly putting pressure on the oil drain plug. Eventually it will break loose, with some help by prying through the access hole. With it still on the jack put two loops of rope around the thing and go find your strongest friend and pull the thing out.
With it on some cribbing on the ground you can now do your "routiine" maintenance. Remember how you took it out, because now you have to reverse every step. I am not impressed with roadtrek for their mounting system or Onan for their unmanageable maintenance procedures. I'll let you know if I ever get it back in.
Thanks - - Jack