Ford 351 in a TS6M Coil Wiring

Toward the end of last season, I had a lot of intermittent ignition performance, meaning when I went to start once there would be spark, on another try, no spark. Swapped out a couple coils and seemed to do the trick, then it just completely went.

This time I have replaced resistor, coil pack, cables, cap, rotor, and plugs, and still no spark. This leads my suspicion to the coil wiring.

I have 3 wires coming from the coil.... Two purples and one gray. One purple comes from the resistor, that one is ground when ign is off, and +14v when ignition is on. I have another purple wire coming from the side of the distributor. It has no ground no power when ignition is on or off. The gray wire (which disappears into the wind of cables working its way back to the front of the boat) has a very slight ground.

Where are these 3 supposed to be as far as (-) and (+) on the coil?

Right now, the Gray and Purple to Disto are on (+) and the purple from the resistor is on (-). This is the way they were grouped in the rubber covers so pretty sure they have been this way. Blows my mind as to why the one with 14v when isolated would go to (-).

I find it odd none of the 3 of these is grounded. My assumption is that the gray was supposed to be a ground and is no longer, and the two purples are supposed to be together on the positive side???

Thanks,

-Matt

After some more online research, it seems that the purple from resistor should be (+) and the disto purple should be (-). Correct? Being that gray and disto purple are paired are they both (-)?

Post which ignition system you have! Points or electonic or electronic conversion?

White or light gray is almost always the tachometer lead!
Purple is very commonly the ignition source power.
Often there will be a start by-pass circuit as part of this. (This circumvents the balast resistor during cranking ONLY!)

If conventional ignition......, purple will power the coil (+) .... whether through the resistor, or as a start by-pass circuit.
The Negative side of the coil (-) is for triggering and tachometer only! No purple here!

Try pulling your hull harnes-to-engine harness connection apart, and examine the pins.
Look for corrosion, etc.
Spray the pins with a corrosion blocker of sorts!
Plug it in/pull apart.... repeat several times!
Take a continuity reading and take a voltage reading!

If you have the electric helix heating element for the choke, make sure that this is not shorting out, and consuming all ignition power..... if configured this way!

P of E.... process of elimination.... one item.... one item only at a time, and you will find the problem.

Thanks Rick.

It is a points system, and I have an "ignitor" electronic conversion kit that I am thinking about putting in. I want to try to diagnose the problem before the conversion if I can.

I am not finding a start bypass. Is it possible it doesn't exist?

If the tach is shorted I should be able to disconnect that in the meantime to trouble shoot right?

Thanks for all the advice.

I got the wires all sorted out, as well as installed the ignitor.

Must have been the points. Started up on the first crank.

There she blows.

Well, good for you!

Don't forget to re-set BASE advance, and to check your TA... (total advace)!
This is very important for a marine gasser!

.