Replacing Spark Plug Wires to Coils - 1957 3hp Seahorse

[Captain Caveman]

This is for a 1957 Johnson Seahorse 3hp (JW-13). One of the spark plug wires is bare to the wire in a spot. I've got the flywheel off and have new wire, but am stumped about how to swap out the wire. Do you just pull the old wire out of the coil and somehow shove the new wire into place and voila? I included a picture below, as it looks like these are aftermarket coils.

At the bottom right, you can see a little of where the wire insulation is worn/chewed away. At the bottom center, I pointed to where the existing wire enters the coil. I don't see screws or tightening bolts. Do you just yank this out and push the new wire in or do you have to buy a new coil with the wire already installed?

 

[Joe Reeves]

Re: Replacing Spark Plug Wires to Coils - 1957 3hp Seahorse

Inside the coil(s) is a pointed prong that is somewhat tapered. Unscrew the present wire, then before inserting the new wire, cut away a short amount of the insulation and fold the wires back against the insulation, spray a little WD40 on the wire (lubrication) then screw it into that prong.

 

[Joe Reeves]

Re: Replacing Spark Plug Wires to Coils - 1957 3hp Seahorse

(Duplicate/Error... Disregard)

 

[HighTrim]

Re: Replacing Spark Plug Wires to Coils - 1957 3hp Seahorse

As Joe said, they just twist on. Pull the old wire out, I like a dab of dielectric grease into the cavity before twisting in the new wire.

I find it easiest to pull the mag plate and coils to do this with ease. Then reinstall. Gives you a chance to clean everything up and regrease the bottom of the mag plate.

On the spark plug boot end, do as Joe suggested and cut back the insulation, fold it back over itself, then insert the spring and spray with WD40 before sliding it into the boot.

Use copper core stranded plug wire. Not graphite auto wire.

 

[Joe Reeves]

Re: Replacing Spark Plug Wires to Coils - 1957 3hp Seahorse

Copper core as High Trim states is fine, but if not readily available, stranded steel wire has been used for many years in the past and works fine (what I've always used).

 

[Captain Caveman]

Re: Replacing Spark Plug Wires to Coils - 1957 3hp Seahorse

Thanks for the responses.

Last night I removed the coil from the plate, twisted out the wire from the coil and then twisted the boot off at the other end (and removed the metal spring). So when you say to fold the wires back after cutting back the insulation, I'm a bit confused. There is just one copper wire in the center. Inside the coil there was just a wire pointing straight out of the opening. Am I supposed to fold the new wire back in the shape of an 'L' approximately 90 degrees so that when I twist it into the coil, it hits the wire pointing out and makes contact? Maybe I'm not understanding the process.

For the boot end, I just pushed the leg of the spring through the insulation about 1/4" back from the end. That's how I found it on the old wire. Then I pushed the spring & wire back into the boot. That seemed right but someone can correct me.

Last question. Someone mentioned greasing the bottom of the coil before putting that back on the plate. I didn't see that step in my manual. What kind of grease are we talking...dialectric or something else?

 

[Joe Reeves]

Re: Replacing Spark Plug Wires to Coils - 1957 3hp Seahorse

Some one at one time has installed the wrong type wire if there is only one strand of wire in that HT lead. I would assume that it would not flex very good being a one strand lead. The normal spark plug wire inner core wire consist of many strands to enable proper flexibility.

Greasing the bottom of the coil?? I started out in this line back in 1960.... never heard of that one!

 

[HighTrim]

Re: Replacing Spark Plug Wires to Coils - 1957 3hp Seahorse

Sorry the grease was for the bottom of the mag plate, just grease lightly. Keeps the mag advance from sticking and lets it operate smoothly. Too much and you could foul the points.

The dielectric grease I put a dab of into the cavity that the pin is in where you twist the plug wire into. Protects it.

Are you sure it is not stranded wire twisted tightly into one? On the boot end, I cut the insulation back, fan out the individual wires and fold them back. That way you have contact against the coiled part of the spring as well as where the pin punctures through the wire. Try to get the pin exactly through center and the coiled part butted tight to the end of the wire.

 

[Joe Reeves]

Re: Replacing Spark Plug Wires to Coils - 1957 3hp Seahorse

On the boot end, I cut the insulation back, fan out the individual wires and fold them back. That way you have contact against the coiled part of the spring as well as where the pin punctures through the wire. Try to get the pin exactly through center and the coiled part butted tight to the end of the wire.

In full agreement.... I've always done the same.