I have a 115outboard 4 stroke,my problem comes and goes, when my 15 amp blows in the motor fuse box im stuck on the water. I have new ignition. Now it

[Tcorrea04]

I have A 115 horsepower 4 stroke mercury engine. It keeps blowing the 15 amp fuse in the motor. Ran great than at the end of the day it kept blowing fuses. Today I was working on the negative side of the battery trying to eliminate any ground problems. Would you know it I could not get it to blow a fuse. It's done this before . That's how I got Stranded on the river. Please any help