Short to the starter?

i have an 82' 633csi and the guy i just bought it from said sometimes you need to push the fuel pump fuse and try to start it, but now it seems that theres a short to the starter. it doesnt turn over, only clicks like a dead battery but battery levels are at 100% help?

I have found many times on 633 and 635's that if the cars are not used much the starters become sticky and they need a tap with a piece of metal on the solinoid to start it and most times this will cure it.