Re: 94 Yamaha I/O CPU [Igniter] "Brain"
There is no test for the CPU. They have a flow chart for checking the sensors but nothing for the big money item. I would say the CPU isn't the problem if its blowing fuses. I would be checking the wiring harness for a ground somewhere. If there is a fuse at the dash for the ignition, then its a non Yamaha item. It was added by the boat builder and may control more than the ignition of the engine. The Yamaha main fuse is located behind the port cylinder head in the black plastic cylinder. The small fuse on the front starboard side of the engine controls the tilt and trim.
