In my experience, starting any 6 volt vehicle is a learning task. I drove my '41 GMC/228/4sp/6volt to work for several years. In my case, choke out 1/2, throttle open about 1/4, crank the engine over 4 or 5 revs and let go of the starter. It usually fired right up. On a six volt when you are cranking it pulls most of the juice so you don't have a good spark, so by cranking just enough to pull a good charge into the cylinders and letting go of the starter you get at least 1 good spark and you have a 1/6 chance that one of the pistons just went over TDC and is ready and willing to fire. Start with a fully charged battery, cranking till it stops doesn't do a thing but heat up the starter and makes you upset. Like I said, just my experience.
Tim
