Which wires go where on coil?

[uncle-buck]

I am replacing the coil on my 1990 Nautique which has a PCM/Ford 351 engine. Polarity is indicated on the new coil, but not the old one. Which wires go on the Positive(+) side of the coil, and which wires go on the Negative(-) side? Thanks in advance.

[tryan]

the negative post on the coil is generally hooked to the points and the tach feed. the positive terminal is generaly hooked to ballast resistor. if you have the pro-tech, repost.


coil are a tough thing to kill. are you wired thru a ballast?

[uncle-buck]

Thanks. Yes, it is wired through a ballast.

[nms1991]

the purple wireas go to the positive side and the black wire and grey wires go to the negative side.

[EchoLodge]

Coil

I just replaced my coil this weekend and can confirm... purple positive and gray negative. This is my boats third coil. It has 860 hours. I always thought coils were bullet proof. But second my boat feels like it is missing under load and at high rpms. A $20 coil has always fixed the problem.