Spark Plug thread problem.

[LAKERJOE731]

I have an 85hp merc around 1975-76 and when I replaced the plungs I had difficulty treading one of the new plugs into the block, I think I messed up the threads on the block. Is there an easy fix for this kind of situation that you could recommend?<br /><br />Thanks <br /><br /> Joe

 

[randycc58]

Re: Spark Plug thread problem.

you'll need to chase the threads. tool available at you local parts store. READ AND BELIEVE. make certain that no shavings enter the engine. they will score the cyl. wall. or you can pull the head and take it to your local machine shop and let them do it. would allow you to inspect the cyl walls while its off.

 

[DHPMARINE]

Re: Spark Plug thread problem.

Joe,I know your engine.There is no cylinder head to take off.But get the thread chaser,grease it to contain the chips and go to it.If the threads are gone,try your auto parts store for KD Tools,thread insert.<br />DHP

 

[dcm3372]

Re: Spark Plug thread problem.

I had a similar problem on a 1963 Evinrude but it was quite cheap to fix.<br /><br />I took the head down to an engineering company and had them insert a helicoil costing only £15 in total.

 

[fishhead24]

Re: Spark Plug thread problem.

Get in touch with a Mac Tools; Snap On; Matco; Tools distributor, they sell a rethreader that you insert all the way into the cylinder past the threads, then you tighten the end , which expands the end in the cylinder. Then you turn it out through the spark plug threads. It works great. It pulls all debris out with it, so none can get in cylinder!