Starter issue and new fuse-I think that there's a short somewhere

I replaced fuse number 14 in my '83 300D fuse box the other day since I noticed it was blown. I just recently bought this car in April and one of the problems I was knowingly inhereted was a starter that would not disengage from the flywheel when the engine was started. The problem miraculously stopped before I drove the car home, and I have not had the issue until after I replaced the fuse. Again, the starter will not shut-off after turning the ignition switch and starting the engine. I think that there is a short in the circuit somewhere, but I don't know where to start looking. Any ideas?