spark plug hole stripped

[out2c]

just bought a boat with a 1965 johnson outboard. Fired it up today to see even if the motor worked. It did. went to check the spark plugs and one came out with metal shavings...and the spark plug wont screw in now. it is pretty loose....so what isthe solution?



thanks Jeff

 

[Tim Frank]

Re: spark plug hole stripped

Depending how much small engine work you do, i.e. how comfortable and competent are you already, you can buy a kit (there are a few different kinds....brands) that will allow insertion of a threaded insert that will be an effective repair.
If that is too intimidating, you could remove the head (pretty simple) take it to an auto or marine machine shop....let them do the repair, and reinstall the head with a new gasket.

Or....take the motor and have the whole job done at a marine repair shop.

Whatever option you choose, there is an almost limitless amount of assistance and advice available in here.
But you will be asked for year and model number....and will be advised to get the OEM service manual for that motor.

Good luck.

 

[out2c]

Re: spark plug hole stripped

Thanks for the fast response...think ill look into the kits....thanks again!!

 

[alangf]

Re: spark plug hole stripped

KD makes an insert but most people I know use Heli-coil. If done properly a heli-coil can be installed without removing the head as long as the plug hole is accessible. The secret is to coat the tapping tool liberally with wheel bearing grease so it catches all the shavings. I expect all outboard shops will be familiar with Heli-coil. Good luck!

 

[rusirius]

Re: spark plug hole stripped

Allow me to introduce you to your newest friend...

The Helicoil... You can pick up a kit (comes with insertion tool, coils, and tap) at just about any marine dealer, auto parts dealer (i.e. napa, pep boys, etc) and other places as well...

Basically you drill the hole out a little larger... Tap it with new threads, and then insert the coil into the new threads and it makes new threads the same size as the old ones...

Make sure you get the spark plug version of course... Go ahead and pick up a head gasket while you're at it and do the work with the head off... Don't wanna risk getting shavings down in the cylinder...

 

[tx1961whaler]

Re: spark plug hole stripped

I use Heli-coils.......for everything but spark plugs. I've read some real horror stories about them letting loose (probably not done correctly) and really hurting people. I've had the holes welded, redrilled and tapped for not so much money. But there's no reason for a properly installed heli-coil to be weaker than the original, especially if fixed w/ the permanent loc-tite.

 

[Mark_VTfisherman]

Re: spark plug hole stripped

......Make sure you get the spark plug version of course... Go ahead and pick up a head gasket while you're at it and do the work with the head off... Don't wanna risk getting shavings down in the cylinder...

I have done this many times, and a few times it has even been my fault :redface: ('83 Nissan pickup and a mid-sixties Johnson 40hp.)

You can do this with the head on. I like the threaded sleeves instead of the helicoil, but have used both without problems. Take a really soft knit and toothy cotton rag and cut a long strip about 4 or 5 inches wide. Poke it into the spark plug hole you are going to rethread with a screw driver. Don't push it in deep- leave it touching the head. Tap the hole, vacuum it out, snake the rag out with a bent wire to bring out all the metal shavings, run in the insert according to package directions. I have never had a problem with metal filings using the soft cotton rag method.

Note that spark plug torque is usually fairly low- sometimes just a few foot pounds. And spark plugs in an aluminum head don't come out as well when the head is hot. Always start your plugs and run them well in by hand, not ratchet. After the metal gasket seats by finger tight, then you can torque it properly.

(If you feel you have to remove the head, you need a manual so you have the right torque specs.)

Done.

 

[kenmyfam]

Re: spark plug hole stripped

Helicoils are just fine to use. Personally I would take the head off to make sure no shavings stay in and damage your motor. Buying a head gasket is cheap insurance in this case. I have had 1 helicoil in my motor for the last 4 years with no issues however I always carry one of my spare plugs with a helicoil on it just in case I need to change that one out on the water and the helicoil comes out with the plug.

 

[wbeaton]

Re: spark plug hole stripped

I use the Sav-A-Thread HeliCoil kit available from NAPA auto parts. It is so easy to use. You just thread the tool into the spark plug hole and it will cut the hole larger and thread it for the insert all in one motion. Then put some LocTite on the insert and thread it in. Give it a couple taps with the provided tool and let the LocTite set. Some folks also swear buy TimeSerts. I've never used one so I can't comment.

Whatever you choose, you need the 14M 1.25 spark plug version.

 

[EARLS BOAT]

Re: spark plug hole stripped

If You Have Have A Marine Salvage Place Near By You Might Look Into Buying A Used Head. I Dont Know If That Is Any Cheaper. The Helicoils Work Just Fine.

 

[Mark_VTfisherman]

Re: spark plug hole stripped

The last spark plug insert kit I bought cost about $35 including a bunch of different lenght inserts, the tap, and the peening mandrel. There was no head removal and used the stuffed-rag routine, back up and running in less than ten minutes, no machine shop costs or extra parts. It's really quite simple. I have even done it on purpose to a VW Beetle engine.

I'd be pretty careful on a 2008 eTec if I had to do it, but on a '65 Johnson? Not much risk there.

 

[alangf]

Re: spark plug hole stripped

I have done this many times, and a few times it has even been my fault :redface: ('83 Nissan pickup and a mid-sixties Johnson 40hp.)

You can do this with the head on. I like the threaded sleeves instead of the helicoil, but have used both without problems. Take a really soft knit and toothy cotton rag and cut a long strip about 4 or 5 inches wide. Poke it into the spark plug hole you are going to rethread with a screw driver. Don't push it in deep- leave it touching the head. Tap the hole, vacuum it out, snake the rag out with a bent wire to bring out all the metal shavings, run in the insert according to package directions. I have never had a problem with metal filings using the soft cotton rag method.

Note that spark plug torque is usually fairly low- sometimes just a few foot pounds. And spark plugs in an aluminum head don't come out as well when the head is hot. Always start your plugs and run them well in by hand, not ratchet. After the metal gasket seats by finger tight, then you can torque it properly.

(If you feel you have to remove the head, you need a manual so you have the right torque specs.)

Done.

Everyone has their favorite methods. I have used wheel bearing grease on the helicoil tapping tool well over 300 times and never had a problem with shavings. There is often more than one right way to do things. I would recommend using whatever proven method you are most comfortable with. Most problems with spark plugs in aluminum heads is caused by failure to use the recommended antisieze compound.

 

[jonesg]

Re: spark plug hole stripped

Most problems with spark plugs in aluminum heads is caused by failure to use the recommended antisieze compound.

For me it was the sparkplug too tight and then one hot run is all it took.

 

[Mark_VTfisherman]

Re: spark plug hole stripped

For me it was the sparkplug too tight and then one hot run is all it took.

Ya- that is what I figured I did to the Nissan. Threaded in fine on the previous plug change, finger tight and nice and smooth. Tightened it by hand, 3/8 ratchet. The next time I took it out I had to get a 1/2 ratchet with an extension handle to turn it out. It brought a bunch of galled aluminum with it. That was my introduction to helicoil- didn't know what they were before that!