For Hurricane Sandy here in NY North of the city I had no power for about a week - after the first day I found Propanecarbs.com and for $175 got a kit to convert my gasoline 5,300 watt Briggs and Stratton Storm Responder generator to natural gas or propane. Gasoline, propane and natural gas engines are all constructed the same and are relatively cheap compared to a diesel engine which is expensive to build. The conversion is so simple, you slide the air cleaner off of the front of the carburetor, screw on lengtheners for the two threaded studs then slide the new gas ring up against the carburetor then the air cleaner back on. You also have to mount about a 6" diameter gas regulator onto the generator (If you only have a plug in electric drill make sure to drill the holes before you shut your power off and take the generator apart
- I strapped a wood board onto the generator temporarily and hand screwed into the wood).
I had a natural gas connection for a BBQ so I connected to that. It's 3,412 BTU's per KW so 5,300 watts is 18,083 BTU's - about 1/2 of a 3 burner grill. That gets me 20 amps of 220v or two 120v 20 amp circuits however you want to slice it. My boiler is like 80,000 BTU's and I can run that and a say 36,000 BTU BBQ at the same time so there's plenty of capacity in my service.
So to run on natural gas instead of gasoline you shut off the gasoline petcock while its running, run it out of gasoline, get it running on natural gas then adjust the fuel mixture screw on the regulator until the RPM is the highest - smoothest. Then I went a little rich just to drop the RPM a bit and know that I'm on the rich side - lean can hole a piston. For propane you would just adjust the mixture again. There's no timing change, no spark plug change - no nothing to do really, its so simple. Even though natural gas does, I think, burn cleaner than gasoline there are other chemical byproducts of natural gas combustion which also contaminate the motor oil so the oil change interval of 50 hours stays the same. So there it is - Tri -Fuel for $175. They sell them that way new also. Last year I ran on generator 24 hours a day for 6 or 7 days and my natural gas bill that month was only $60 higher - amazingly cheap compared to gasoline.
So if you have natural gas or propane Tri-Fuel is a great choice. For a remote place with a permanent mounted in place generator I think that Propane is the best choice because there are no fuel aging, water in the fuel, fuel jelling in the cold (diesel fuel) problems. And, although fuel stabilizer for gasoline is nice - dead dry I think is nicer - 5 years during which I didn't need mine at all went by fast.