Starter motor problems

There's a funny problem the DeLorean can suffer. The symptom is the gearshift suddenly goes really really stiff.

There's a 2-foot cable that does the crossgate and is the only remaining ground path if the main engine-to-chassis strap fails..... it gets rather warm and has a plastic outer sheath....

Morning. My starter motor was playing up (which lead to some exciting bump starts on snowy hills) and after doing all the usual electrical checks and technical taps I just got the thing recon'd for about £80 and it starts more eagerly than before.