A quick method of waking up an engine like that would be to disable the ignition by disconnecting a coil primary wire and spinning the engine with 12 volts after putting a little oil into the cylinders. 12V won't hurt the 6V starter at all if you limit the run time to 10-15 seconds at a time. Once it's spinning freely, then be sure you've got a good fuel supply and hot spark and go for a try at a run.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!