So you're saying the starter will not crank the engine? That info was missing from the original post...
9.4 volts won't do it, as you know. With a charger hooked up, and the battery at full charge tho, it should. Depending on which terminals you "jumped", you can either just spin the starter motor, OR engage the solenoid to pop the bendix out while the motor is spinning. When jumping to crank the engine, you need to connect the large center terminal with the smaller terminal closest to the engine block. This will both spin the starter motor, AND engage the bendix. If you jumper to the lower terminal of the solenoid, the one that has the small bolt holding it to the starter motor, it will spin the motor, but not engage the bendix.
You should also check to see if you have a full 12v at the purple wire on the solenoid while trying to start with the key. If you don't have a solid 12v there with the key in "Start", you have either an ignition switch, neutral switch, or wiring problem.
hth
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