Help

by Rex wiley
(Louisiana)

I habe a 1991 johnson 140 hp there is a small bus fuse on the motor by the starter if you turn key on it blows fuse if u hit trim it blows fuse oy thing on this battery is the motor. I chanhed batt terminals changed ignition switch and changed 40 amp breaker on motor i know its a short or grounding out but idk where to look any ideas?