I have a mid eighties 75hp merc outboard. It has always ran well but now has started blowing a 20 amp fuse under the cowling whenever I turn the key. Sometimes it will turn over for a few seconds before it blows, sometimes it just clicks a couple of time and then blows. I have gone through about 10 fuses trying to find the problem. Randomly on the weekend is started right up. I thought it was good, but the next day it was back to blowing fuses. I have checked the wiring from the controls to the motor looking for shorts and I don't see anything. The wiring under the cowling doesn't show any signs of shorts. I'm out of my league here and need some help. Anyone have any ideas?
