DC Motor help

hi again.

i have tried adding a 4700uF capacitor across the power supply but this doesn't solve the problem. The circuit still behaves erratically with it running normally for a period of time before cutting out. The circuit can then be started again but the same thing will happen (usually after a progressively shorter time).

i'm really beginning to tear my hair out with this!!

Can anyone suggest anything else?

that actually sounds like something is overheating