Change the starter drive. It has a one way clutch built into it to prevent overspeeding the armature when the engine starts, and if it fails it will slip both ways. Since 6V and 12V starter shafts are different diameters, it's difficult (but not impossible) to use the wrong one. Some guys are just too talented when it comes to using a BFH!
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!