I've used carburetor cleaner spray, as a "primer" or starting fluid for small gasoline engines, spark starts it pretty well, and the engines run for a bit before the burn it off, I suspect it would somewhat work in a diesel, not as vigorously as ether. And maybe a drop or 2 of gasoline into the intake, would be enough vapor to light off a cold engine, or one just a bit low on compression. But propane does not light well from compression at all.