I was quoting the manual, the older Briggs were adjustable at the coil as to advance/retard the timing.
This wasn't something new or revolutionary at the time the manual was printed as spark plug engines have been running on kerosene since the 20's to my knowledge, more than likely much before that.
We still have a John Deere A, vintage est 1931. It has a one quart tank intergrated into the main fuel tank designed for gasoline, and the main tank for kerosene. It has a dual valve in the fuel line to switch between fuel supplies, you started on gas then switched to kero.
You had better remembered to switch back to gas prior to shutdown because it is almost impossible to start on kero, even at 90f as this tractor is old enough to NOT have electric start, you start by opening compression relief petcocks on the heads then roll the flywheel to start. I had MANY revolutions on this tractor when young as we used it well into the 80's to mow and plow snow.
I wouldn't worry about fuel dilution as these engines are almost indestructable and the directions for switching come right from the manufacturer.
Briggs also stated to expect 15-25% reduction in power running on kerosene, and also approx 20% reduction in fuel consumption.
