Stripped spark plug hole threads

[djohnson52]

After replacing 11 spark plugs without issue, On the last one I somehow managed to strip the first two threads inside the spark plug hole.

I tried to use anti seize on the plug after noticing they were stripped and gently thread it back in but the spark plug got bound again. Is it possible to use a thread chaser since it is only the first couple threads that are damaged, or is that going to cause me more issues. I am having the tech at the marina look at it on Monday to get an expert opinion.

Anyone run into this before? Any ideas to resolve would be greatly appreciated.

 

[freddy063]

What motor? I would say as long as it is tight and not leaking , run it. What did the plug look like, and when was the last time you changed them?

 

[djohnson52]

It is a 2001 Yamaha 150 hpdi. The plugs had not been changed for about 2 years. They were pretty dark brown/black when removed. They all came out easy I just must have gone in at a weird angle on the last one or some junk was stuck in the threads that I did not see.

My concern is wearing the threads down when putting the plug in and it will not have any threads to hold it in place. I have heard of instances where the plug was blown out when running because the threads were worn down. Thanks.

 

[Harpoon]

I had that problem a few years ago on a 250 ox66. I bought a new head and gasket from boats.net and replaced it right at the dock. Be sure to clean old gasket off completely without damaging mating surfaces. also you'll need a torque ( i think it was 20 ft-lbs) wrench and you need to know the recommended tightening sequence.

It was way cheaper than having the head fixed by a marine shop.

 

[gw204]

If you are going to try chasing the threads, I would pull the head off to ensure you keep any trash out of the cylinder. Once off you might be able to straighten them out by running the plug in from the piston side. If it ends up being boogered up too bad, I would buy a used head off of ebay and install it with a new head gasket.

 

[Another Distraction]

PM me your number. I'm in RI, this is an EZ fix.

 

[Tucker]

Well how about sharing your easy fix with the rest of us.