Merc 3.0L with no spark to motor

[j_pete003]

I have a Maxum 1700SR with a Quicksilver 3000 Classic. Took the family out on the boat and ran fine for about a 1/2 hour when the engine quit. Upon some trouble shooting, it's getting fuel. I checked the fuses and found the 15 amp fuse blown. Growing frustrated with the kids, I used a piece of wire to "jump" where the fuse was. A couple minutes later the harness behind the controls started smoking. Not the smartest thing I've done but.... I can't figure out how to take the Quicksilver 3000 classic apart to take a look at it. The smoking wires come from the kill switch on the controls. Can some one tell me how to by-pass this switch or how to replace it? Where do the wires go to the engine that I smoked?

 

[CharlieB]

Re: Merc 3.0L with no spark to motor

The damage is already done, but you want to be sure NOT to create further problems during your repairs.

That fuse supplies the ignition switch which powers the accesories in the dash and powers the trigger to the starter relay.

The motors ignition is a 'ground-to-kill' self energizing by the rotation of the flywheel magnets to the stator coils.

The ignition switch is TWO switches in one. One switch turns 12 volts on to the accessories and triggers the starter, the 2nd switch grounds the ignition system when turned to the Off position.

You have a short somewhere in the accessories, replacing the fuse allowed current to continue until wires melted, burning into the motor ignition system on the kill wire.

Replacing the boat side wiring harness and ignition switch may be the quickest and easies method of repairing most of the damage,
HOWEVER,
The motor may not start, if 12 volts fed back into the ignition system it WILL damage components.

You will also want to test each accessory to find the cause of the short. Depending on the location of the melt down it may be isolated to a bad ignition switch.

It's a bit late now, but in the future, when a carbed outboard blows fuses while at sea, UNPLUG the large canon plug connecting the boat harness to the motor harness, then take a peice of metal and jump the starter relay to crank and start the motor to get to shore.