I have a 1989 Mercury 45 HP. The fourth (bottom) cylinder was not having any sparks. I took the boat to a mechanic and he told me that the switchbox was bad. He replaced and tested it. All four cylinders had sparks. I took the boat to a lake test and it ran ok for five minutes and then it quit. I restarted and it was running ok in neutral, but when shifting forward, it was dieing. I tested the cylinders again and the two bottom ones (third and fourth) had no sparks. I am lost, helpppppp. Thanks, JR.
