Johnson/Evinrude Magneto Coil Grommets/Boots

[OB1]

I’m currently in the process of fixing up my recently acquired ’59 Evinrude 18hp…

After installation of new wires and ignition components, I came to the realization that I didn’t install any coil grommets/boots/seals when I replaced the wires. This was because the old motor didn’t have any. At the time of installation it didn’t dawn upon me that I needed these. Now I’m debating with myself if I should bother installing some or not.

My research seems to indicate that the earlier 50’s magnetos didn’t have the boots. Looks like they added them in around ’56.

So… is it a concern or not? I did put a generous amount of silicone compound in the cavities when installing the wires. So I don’t think corrosion is big concern. Also, I don’t see that they are buying very much in terms of insulation.

What do the experts here think?

A. No big deal. Don’t worry about it.

or

B. You will get stranded far out at sea without those properly installed.

x

[crosbyman]

chinese coils don’t come with boots so I try to reuse old ones but… I have installed several 7mm wires with just dielectric grease to keep moisture out.

you could dab some silicone on the external rim of the coil and wire but I would not put silicone inside the coil so as not to mess up continuity. make certain you screw the new cables on the screw HV pins about 3/8 inch.

I guess now you should just measure coil resistance to ground to ensure you get 4-7 Kohms you should be good to go.

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[lindy46]

Yes, dielectric grease is adequate. If cables are firmly installed on the coils, the hold downs on the bottom of the mag plate will hold them securely and prevent them from coming out of the coils.

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[fleetwin]

I wouldn’t worry about it….Just add the grommets/covers the next time you service the ignition…

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[seakaye12]

You can use the appropriate diameter marine shrink-wrap tubing, Better than the boot. Marine grade has an adhesive lining that activates with the heat….so you get a waterproof seal. Just cut a piece to length; an inch or so….and bring the one end of it up onto the coil .

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[crosbyman]

Good idea !!

worst case….. dielectric grease inside and a regular shrink wrap is what i’ll do next time (I have no marine shrink wrap)

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[Mumbles]

I tried shrink wrap once on some Chinese coils but then the coils wouldn’t fit into the mag plate. Instead of grinding out the mag plate, I just cut it off. Since I’m a fair weather sailor these days and my motors only get used on nice days, the mags don’t get wet or damp. The original boots might have helped to hold the wire in the coil but since the replacement coils have threaded pins and 7mm wire fits quite snug with some silicone grease on them, I don’t really think boots are really necessary.

• This reply was modified 3 years, 5 months ago by Mumbles.

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[OB1]

OK – Thanks for all the advice and insights. I think I’ll just leave them bootless.

• This reply was modified 3 years, 5 months ago by OB1.

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