I don't think you loose power, just MPGs, as there is less thermal energy
in propane, and as far as flow below 20* that's not a problem, but getting
the liquid (the L in LPG) to boil or evaporate is the problem, that's why
a propane carb has heating jackets in it, to boil the liquid to a gas so it will
burn, liquid, be it gasoline, diesel or whatever doesn't burn well
Wild