I recently bought a boat, 1990 17.5' Glastron 4.3 Merc. I/O. I ran the boat for 30-40 minutes to test without any problems. After a day of running skiers and cruising I was driving it toward the trailer when it just stopped running. 
At the same time the tilt would only go down, not up. The radio worked, and the guages all read when I turned the ignition key, just no ignition. I jumpered the wire on the tilt pump, and it worked that day to go up. The following day the motor started and the tilt worked fine several times up and down constantly. <br /><br />Any ideas? I suspect the switch, but could not find anything cracked or corroded.
At the same time the tilt would only go down, not up. The radio worked, and the guages all read when I turned the ignition key, just no ignition. I jumpered the wire on the tilt pump, and it worked that day to go up. The following day the motor started and the tilt worked fine several times up and down constantly. <br /><br />Any ideas? I suspect the switch, but could not find anything cracked or corroded.