We have an '03 3510 on a Workhorse chassis, that we enjoy. The previous owner was not much on routine maintenance or cleaning but we haven't found any serious problems. We bought it for a price which would have allowed for considerable repairs if necessary.
The genset cranks and runs off the house batteries. With the engine running, you are charging the batteries with the alternator. Hopefully your house batteries are just low.
Well, I think most gensets are started by the chassiss batteries not the house. At least mine do and any I know of.
How about that. I've had two Winnies, an Allegro, and a Coachmen, and they all cranked from the house batteries.