Predator engine products do well.
The engines are made in China by Loncin. You're not gonna get 1500 hours out of one engine but I'd expect around 600 hours with proper maintenance.
If it's a 212cc Loncin 210FA parts will work.

That's a very good idea, especially since splash lube engines don't utilize a filter.

I put one of them in ours along with a big wheel conversion so it will actually roll on something other than flat, smooth, concrete!

We tried running our furnace on it and it will not run on a generator or possibly just an inverter generator?

I need to see if a transfer switch like the ones posted earlier would fix the problem?

You would need a big generator to run most furnaces.

Thanks very much. Great ideas.

It is just a gas furnace on a 15A breaker.

The fan would come on and run but something about the board not reading something right causes it to lock out.

I am sure the old style furnaces would run without a problem but the more advanced something is the more problematic it can be.

Gotcha, I thought you were trying to run an electric hvac unit.

The transfer switch will not make any difference. It is just a convenience item for switching to an alternate power source.
Are you SURE your furnace runs on only one 120V phase? It's quite possible that both phases are routed to the unit, with one used as power to the motor case proper, and the OTHER phase to the power supply for the controller board. So, while a unit may not have a 220V motor, it may require both phases to be energized. Many small inverter generators supply only one phase. I suspect that is your issue. You always need to be cognizant of surge amps for startup, which are often double the running amps. Example: a motor that may run on 5 Amps (600w), may need 10A (1200w) for the start-up surge.

I was reviewing the specs on several generators and saw that most electronic control boards etc are sensitive to the THD produced by the generator. The recommendation was < 5 % is needed for these devices So, I am now a bit skeptical in trying to hook up one of these guys and then maybe burning out the TV and furnace ETC. due to everything these days having a control board.
So has any experienced these issues?

Modern electric devices including control panels do much prefer pure sine wave inverters. Most gasoline/diesel/propane generators at best have modified sine wave inverters

Agree, you’d have to have a very, very, very powerful generator to run an electric furnace.

To run electrical devices under 1500watts (laptops for prolonged periods, or desktops for shorter lengths of time), this is a good option (pure sine wave inverter)

This particular model would probably max out running two small commercial space heaters or one smaller industrial heater