Starter (or something) blowing 20 amp fuse
 

Greetings,

Not sure if anyone can help with this, but it's worth a shot. I've replaced a 1985 MCM 260 with a 1989 320 EFI motor. The pigtail on the motor is only one pin different from the pigtail coming from the helm (pin 4, audio warning). I've checked the schematics over and over. I've double checked the wiring with an ohm meter, everything is wired correctly. But when I turn the key to start, it blows the 20 amp inline fuse.

Two weeks ago I had this engine on the test stand. I made a little switch box, and bought a fairly (don't remember the amp rating) heavy duty push button from the auto parts store. I didn't use a fuse, but the engine ran fine. But after many turn overs, the push button burned out. I just figured it was cheap and couldn't handle the amps.

But now, I'm blowing that 20 amp fuse and wondering if that's what blew my test push button. I've checked the wiring harness on the motor, everything looks fine. The starter is wired correctly, everything is right (I have another 320 to compare to as well). And it started fine on the test stand and I haven't done anything except drop the motor in. So for some reason the starter solenoid or slave solenoid are drawing more than 20 amps. Or could it be something else?

I can't imagine the slave solenoid would short out, but it's old and weathered for sure. But I suppose I could wire up a test harness to see if that's what is doing it. Anybody ever seen a symptom like this?

the slave solenoid had a ground wire going to it..could have a internal short....try a 30a fuse first and see what happens...takes about 60 amps to start melting a 14g wire so you have some insurance their..dont forget you now have efi that needs more amps to run..

Yeah I rigged up a test harness, no problems found. So after I got to thinking about it, the only thing new that I introduced was a shift interrupter, since this motor is going onto an alpha drive. When I removed that from the circuit, everything works fine.

So the problem is that the shift interrupter isn't right somehow. I followed the schematics exactly. I even double checked with an ohm meter, but obviously there's a problem somewhere.

I took the schematic below to mean that the green wire connects to the switch as well as the distributor. That's exactly how I wired it, but it's obviously wrong somehow. I even double checked it again a few minutes ago, but something ain't right. Fortunately, with the switch out of the circuit the engine runs, so I didn't fry the ignition.

http://www.vonmiller.com/images/eleganza/schemeIMG.jpg