Originally Posted by
covertcombatant
I would put the D.U.I distributor in and call it a day. I fought my electronic Mallory ignition for a little while. The coils kept overheating and having problems. The boat would miss when the coil heated up and if you were idling waiting for a skier the boat would die. It wouldn't start until I soaked a rag in water and through it on the coil or sat and let it cool down.
Threw the D.U.I distributor in and fires up on the first key turn and can run and idle all day long.
Spend the money and enjoy the boat.
100% Agree. I had a similar problem with my 85 Comp for years and could never figure it out. Turns out it was a bad coil, ballast resistor, and bad wiring.
Another thing to check is to see what voltage you are getting at the positive side of the coil. They typically like to see 9-9.5V; if you are seeing over 10V, I would look at how it is wired (this also happened on my boat...full 12V was being sent to the coil which caused overheating and after time terrible spark".
1985 Supra Comp TS6M
351 Windsor - 240 HP
Velvet Drive - 1:1
Fully Rebuilt