How well do 2 stroke engines run on propane as an alternative fuel?
I have a 50cc scooter that I have thought of converting to propane. It has an oil injector so I don’t have to worry about it getting oil. but by using a camping cylinder to fuel it I wonder how long it will last. Also will the propane and air carry the oil into the engine just the same as using gasoline. I have heard of some using the propane as a boost of power on these small scooters, using it along with the gasoline.
Does anyone have some knowledge of using propane with these small engines?
You are right to be concerned about oiling the cylinders, that is the primary problem with gaseous fuels in two-stroke engines. Propane will not carry oil into the cylinders the same way gasoline will, because propane and oil will not form a solution. The oil would need to aerosolize and become part of the fuel/air mix. I doubt this is possible using conventional motor oils. However, it should be possible to run a blended fuel, for example–50% gasoline and 50% propane. The gasoline would still form solution with the lubricant oil and aerosolize in the carburetor. For proper lubrication the gasoline/oil ratio should also increase.
Propane has more energy per weight than gasoline (46.44MJ/kg vs. 44 MJ/kg for gasoline) but less weight, therefore less energy per gallon (91,690 btu/gal vs. 125,000btu/gal for gasoline). A propane engine running properly should get 73% as many miles per gallon as a similar engine running gasoline.