2001 90-HP Merc dies

Sande Ace

Cadet
Joined
May 17, 2006
Messages
18
Launched yesterday. It was cruising just great when it just quit. Nothing electrical would work including the gas gauge. New battery didn't help. Is there a big fuse somewhere that protects everything electrical in the motor.

Thanks!!
 

Sande Ace

Cadet
Joined
May 17, 2006
Messages
18
Launched yesterday. It was cruising just great when it just quit. Nothing electrical would work including the gas gauge. New battery didn't help. Is there a big fuse somewhere that protects everything electrical in the motor.

Thanks!!
More info. First good, then bad.

I found 2 wires. One was labeled 20A and the other 30A. I opened the "box" and found 2 flat fuses, one 20A and one 30A with a spare fuse each.

I replaced the blown 30A one with the spare. Things worked as they should. I could tilt the motor, the fuel gauge worked, and it would start and run. Great!!!!

The next day (today) I went to the boat and it was completely dead again just like in the beginning of this. Completely dead electrically.

Can just turning the key to "on" blow a 30A fuse? Thanks!!!!
 

Texasmark

Supreme Mariner
Joined
Dec 20, 2005
Messages
14,671
Disconnect the wiring harness in the engine. Install a new fuse. Turn the switch. What happens? If it holds its engine related. If not it's a boat wiring problem.
I had a 2002 90 and it only had one 20 amp fuse internally. Nothing in the service manual about any 30 amp fuse. Another clue is that the fuse box you opened is part of the boat, not engine.

What in your boat uses and could draw high current? I don't know as I never had a 30 amp fuse in a boats fuse panel.

What's interesting, on the Merc. Commander 2000 and 3000 side bulkhead mounted common control boxes, power to the ON-OFF switch comes from the engine to operate the engine. If you had something wired to the switch, requiring a 30 amp fuse, the 20 amp fuse in the engine would blow first.

Only thing I can think of is that the boat has an auxiliary power relay to operate that "thing" that is driven by a 12v energizing coil that is wired to the ON position of the ignition switch. That would allow the load to blow the 30 amp fuse without blowing the 20 amp fuse in the engine that supplies power to the ignition switch.
 
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