I have always wished for a propane start fuel circuit on my truck. These were once very popular in the extreme north where temps drop well below zero. Beside the battery weakening in the cold, the main problem is that gas when it flows through the intake manifold and past the valves ets, it puddles from touching the cold metal. Propane is a gas and not a vapor like gas so it ignites much easier. Propane is compatible with most 4 stroke engines. The proper valving and regulator is all that is required! It would be nice to just hook up your propane tank and start her and let it run a bit and then back to gas! Fuel injection especially port fuel injection has virtualy solved the gas problem, extra battery capacity is a must in the extreme cold, Storing your battery inside in the wood stove warmth helps a great deal, (not actually in the wood stove),, silly! no reason why a small engine would not benefit as well.