this might have been mentioned already, but i think it depends on the engine. i have an electric starter that i got for my os 40 la that would have trouble starting (i couldnt flip start it unless it was warm). i recently bought a plane with an old os 40 fp engine in it. this thing is old. i like it because it flip starts on the first flip even when its cold. so whenever you get an engine that wont flip start, just get an electric starter. you can get an inexpensive gel cell with a charger for the power(also good to power field chargers), or i recommend a jump starter for a car ($50-$60). it has a high capacity battery in it, jumper cables that you can hook your starter or field charger to, a cigarette lighter hole (some chargers use cigarette lighter plugs like the one in your car), a light, and an air compressor (also useful when you get pneumatic retracts for a future plane).