I have a 1979 Evinrude that I had purchased from a guy two years ago and have no idea how long ago the silenoid was installed but I have been using the motor with no problems until yesterday. It did not have a problem starting up for me when I left the dock but then when I was getting ready to start it up to head back in, I heard a click and then I had no power to the tilt and trim or the ignition key. I figured it was a fuse but I pulled the fuse and there was nothing wrong with it.
So I checked the wires leading from the battery and found that one of them had been pinched and had almost corrited to nothing so I spliced that wire together figuring that would have been the problem but still nothing. The fuse is not blown and I can not get the tilt and trim to work or the ignition to turn. Does this mean I need to change my silenoid?
Second, disconnect all cables/wires pertaining to the electric starting system, including the battery terminals and the negative cable ground connection at the powerhead. Clean the cable and wire end terminals and also the components that they attach to. This is eliminate any poor, loose, or tight but dirty connection problems that can and do create a voltage drop to the starter solenoid.
If after the above, you still have the same problem and you're sure that a full 12 volts is present at the battery cable connection of the solenoid, replace the solenoid.
It turned out to be the Power tilt and trim solenoid. I changed it today, it took me a while to find the right solenoid in my area. I connected every thing turned the key and the motor fired right up. I love evinrudes.