Jason, that's a great idea about getting a spare carb. I actually plan to do an immediate conversion to propane to avoid the carb fouling, plus storing propane is a lot easier for me than having fresh gas on hand for emergencies.
The 240V / 4000W model that Costco had last year was dual-fuel, so I'm a bit ticked that I didn't get it before it disappeared from the website. Maybe they'll get it back soon though.
If you do that, you will have a useless POS for what you want to do. You can figure to derate about 20% for LPG! Go back to Champions website and look at the dual fuel generators for Gas/LPG and look at the ratings.
Also keep in mind, they are only 3500W if they will actually pull nameplate ratings. From personal experiences, the only ones I've ever seen pull rated were Onan, Honda and a very few others. Even those when put at nameplate rating loads will trip the breaker as they are being run at 100%, just like trying to run a 30A breaker at 100%. You should not run a breaker at 100%, just load it to 80% max. That's also being run with a pure resistive load, not an inductive (motor) or capacitive load, (Check Power Factor). Most Coleman Powermate brand generators will not pull rated right out of the box, after a little "tweaking on the governor" they "usually" can just barely make rated as the generators are under powered. Onan used to sell a Pro Series, they were rebadged generators with Onan engines, they would always pull rated, they had 14.5 HP engines where others had 8 - 10HP engines. You get what you pay for.
From personal experiences, keep in mind I go to Hurricanes and storms and repower cell sites, I just got back from Puerto Rico working that storm, and saw people trying to do exactly what you want to do. A 3500W generator will not last long even if it does actually start the load you want to run. Running a generator at or near 100% load is not a good idea for extended periods.
LOL, I fixed a Rigid Brand generator for the guard at the gate of our compound. It was a 3250W rated and they ran it at Rated from the looks of it. The Rotor slip rings looked like hell, the brushes were shot and the regulator finally crapped out on them...It'd been running for a week or so...it'd trip the breaker, they'd remove the load, restart it, and step the load back to keep the lights and frig running.
In a bind, I'll take our 3500W and "run the house", meaning I'll power the frig and the TV and lights, we use LED bulbs for lighting. And even doing that I don't feel real good about it using a 3500W generator. But I keep an eye on the Hz and Voltage and monitor the amp load most of the time. But then again, we seldom loose power for an extended time. When the tornado came through I borrowed a 5K Honda until I could dig my 5K Onan out of the shop to run the place. After the tornado, the house had power but the shop didn't. I used the 5K to power the shop for extended runs as it was rebuilt.
IMO, a 3500W generator is good for short run times with light loads, such as a frig and some lights, that's it. But it's you party, invite what you want. A lot of people on here have a LOT of experiences doing or trying to do what you want to do. Go ahead and get a 3500W and try it. It's cheaper to learn from others mistakes. But having a "spare" 3500W does have an upside, so try it. We'd like to see how it turns out.
