Spark Plug threads stripped

[MNOutdoorsman]

Winterizing my 1964 Evenrude 90hp, removed a spark plug to fog the cylinder and thought it felt "funny". When I re-installed the plug, the threads in the head broke out.

Is there a kit that can be screwed in? Do I need to pull the head off? Is this something that should be attempted at home?

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[Surface Tension]

It can be fixed. Googel Heli-Coil.

[Shack]

Ya Heli coil or thread insert! I have seen them done on the the 5.4l and v10 Fords when plug blows out!

I did one this summer on a Honda 100 dirt bike I bought for my kid! He has used it ever since with no concerns. Follow instuction and make sure when over size tapping hole to use a lot of grease to catch chips. Pack grease in flutes of tap and this will catch almost all of the chips from tapping! Then I used a Shop Vac to suck out cly. bore threw plug hole and then kicked it over a couple times. Pop in insert and problem solved! Worked slick!

I looked on line and measured my plug diam... But ended up buying Heli kit from Bumper to bumper. The kit comes with extra threads inserts, so when changing plugs in future and coil comes out with plug, just reinsert a new insert!

Good luck!

[MNOutdoorsman]

Thanks for the info. I have heard of the Heli Coil but didn't know how it worked. I was afraid I would have to pull the head to have it tapped.

I will let you know how it turns out.

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[Shack]

That is the beauty of it! No pulling head!

Just make sure piston is down in cly. and one of the valves are not in the way of the tap. My kids dirt bike, on the exhaust stroke, had the exhaust valve open and in direct contact with tap if I had not turned motor over once more. Just look in plug hole with flash light to see if anything is in the way.

Good luck!

[MNOutdoorsman]

Thanks for that tip. I won't be able to try it until next week. I've been looking at the HeliCoil info on the web and it doesn't look too difficult.

This is a sweet old motor and I want to keep her going.

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[Shack]

ITS EASY AS PIE!

Good luck!

[iffy]

A helicoil repair would work, but if it were mine I'd get on the phone with Tims Outboard in Hackensack. They have tons of used OMC parts. I'm sure they'd have a head sent to you for not much more than the cost of the helicoil. Then just get a new gasket and put it on. It wouldn't be very expensive, and it'd be done right.

[MNOutdoorsman]

That's a good point. I'll give him a call.