Onan Generator Carb question

Hello RV'ers
I am in need of your help,
1995 Coachman, low miles under 25k, just picked it up in the beginning of the summer & used it several times. It sat by our warehouse for almost 2 years not moved at all, the owner of the warehouse gave me a good deal.

Now its parked at our Cottage for a couple of weeks.
Kids wanted to sleep in it & the generator worked but died.

Replaced the battery, replaced the fuel pump which was an after market 12 volt unit, got fuel it starts but sounds like its missing a cylinder & blue black smoke is coming out of the exhaust.
pulled the plugs & they are tar black.
I am running super unleaded since i bought it to keep everything clean so i thought.
It wont accelerate but will die if you touch the throttle.

I called the dealer for parts & the only thing in stock is a coil pack & other odds & ends. Carb is back order #146-0749. Does anyone have any contacts for this carb?

Any suggestions?

Thanks Everyone!