[Christ]

It's in a Briggs manual I have from 1977.. (don't ask)

You basically use low-compression heads, or double stack gaskets on certain models. You use a hotter spark plug (I think hotter, maybe colder, don't have the book right now), and you add a second fuel tank... it technically still starts on gas, b/c the kerosene needs a higher cylinder temp to run efficiently, but once you've warmed up the engine, you can just flip a valve and run it on the kero tank.

Once you're done running it, you can either drain the bowl and re-fill it with gasoline, to ease the next start, or you can let it run for another minute w/ the kero shut off, then turn the gas valve back on.

Briggs says expected HP is about 15 % less, and fuel economy should increase 20-25% using clean kerosene. I figure that since Kero and Diesel share many of the same properties, I should be able to run filtered/thinned out waste oil in the engine as well, which equates to free fuel. It's easy to get used oil around here. We even have a garage heater that runs on it.