I have a mid 90s 40hp Mercury 4 cylinder 2 stroke outboard with an electrical short that has me puzzled. I took the boat out a few days ago, it ran fine, when I got home to flush the motor out, the 20 amp fuse beside the electrical box popped. I installed another fuse and just as soon as I turned the key it popped the fuse again. So I opened the cover to the electrical components, to see if there was a pinched wire, or anything burnt up or came loose, found nothing, I mean nothing. I took my Ohm meter checked each wire I could find to see if anything had went to ground, again nothing grounded that should not be. I took the plug loose that goes from my (throttle, electric trim control box) to the outboard motor, 4 of the pins on the engine side showed resistance to ground, that seemed like a lot to me. When I pull up a diagram of the components within the electrical controls on the engine it shows a voltage regulator, but I do not see one within the panel, I trying to eliminate things, but nothing is showing up. I appreciate any suggestions you might have.