So i have a 71 johnson outboard and last year i took it in to a marina to fix a blown fuse and that same day i tried the motor to see if it ran and it did but then right after i took it off the trailer it blew the fuse again. So i took it back in and my step dad later picked it back up and the only thing he told me they did was disconnect the wires that ran the neutral and reverse so for the past year i have only had forward. So my question is what would cause a fuse to blow while in neutral and reverse? and how do i go about fixing this? looking at selling it soon after the fix to get a new boat so i need this to be a fix for good 
any help would be appreciated 
Derrick 
