HEI conversion issues 1987 Mercruiser 3.0

[KinleeE]

I’ve search the internet for 2 weeks to solve my problem with no results. I have a 1987 3.0 Mercruiser that I changed the points to EI Protonix and flame thrower 3.0 ohm coil. A lot of directions call for taking the purple wire off and running a wire from positive side of the coil to the ignition switch hot side or to the alternator. I unhooked purple resistor wire, ran a 12 gauge wire to the switch. FIRE!! Melted the positive wire for the distributor to the coil. Also boat wouldn’t stay running but did fire trying to start. Removed wire to switch, reconnected purple wire after tapping the melted wire covering. Fired right up. Second attempt- removed purple wire and ran a hot wire from coil to the alternator. Same issue but no FIRE. Boat tried to start but didn’t. So with all that information my problem is this. Boat starts and idles great. Boat runs great until about 1/2 to 3/4 throttle. Boat motor stops running at that point but starts right back up. I suspect a voltage drop but can’t figure out the issue. I don’t see a resistor anywhere. Anybody else had the issue before. Any suggestions would be great

 

[alldodge]

ran a 12 gauge wire to the switch. FIRE!! Melted the positive wire for the distributor to the coil.

There is something miswired or something is wrong the the Petronix.
Don't like the Pet but when it does work there is no issues

It melted the wire but didn't blow the 20 amp in line fuse under the helm, doesn't make sence

 

[achris]

Here's what you original wiring should have looked like...




Here's what it should look like with the Petronix in..


I would run the new power wire (purple if you can find it) from either the choke or the alternator purple. I would also attach a new black wire to the distributor body and run it to a known good negative point (incorrectly called 'ground').

Chris.....