Should I Run Onan 11,000-Watt Tri Fuel Generator on Gas or Propane With Two AC Units

Updated 08/18/2026 | Published 08/14/2026

Question:

Hi guys, I'm mainly buying the CM98MR to run both AC units on our 50 amp 5th wheel during summer camping. Is there any advantage to running it on gasoline instead of propane when I'm putting that much of a load on the generator?

asked by: Eric D

Expert Reply:

Hey Eric! I would run the Onan 11,000-Watt Tri Fuel Portable Generator # CM98MR on gasoline when you want the most available power for both AC units. It produces 9,000 running watts on gasoline compared to 8,100 watts on propane and 7,200 watts on natural gas.

Propane is still a great option when you don't need the generator's full capacity, especially since you're already carrying it for your 5th wheel. However, when it's really hot and you're those AC units along with other appliances, I'd use gasoline for the extra available capacity.

What size AC units do you have on your 5th wheel?

expert reply by: Robin H

Tri Fuel Portable Generator
(click to enlarge)

Eric D.

8/18/2026

Thanks Robin! We have two 15k AC units so it sounds like gasoline will be the way to go when we're running both.

Robin H.

8/18/2026

@EricD you're welcome! With two 15k AC units the # CM98MR will be a great option. I'd stick with gasoline when you're running both so you have the full 9,000 running watts available.