Leaf vac engine: stripped sparkplug threads

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  #1  
Old 11-12-12, 11:55 AM
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Leaf vac engine: stripped sparkplug threads

Got what I paid for: next to nothing for a leaf vacuum with a Tecumseh engine. Cleaned out the carb and it worked pretty well... and then the engine spat the spark plug out. It made a pretty impressive POP! and threw it 6 or 8 feet. I figured the last owner had installed the wrong plug, and replaced it with another plug. That other plug was likely also the wrong one but it fit, or threaded in at least, and then last week the engine spat the plug out again.

I researched and got a correct replacement plug, but now the threads are stripped and the plug won't thread in at all.

Is there a fix for this? In my mind's eye I envision a large-ish tap and a spark plug to work with the new threads. Am I close?
 
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Old 11-12-12, 12:01 PM
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Can't say I've ever heard of anyone spitting out a plug before....
I would think it could be possible to tap the threads. I'd do my research first on what size of plug would be the next size up, but still meet the temp and length requirements.
Tapping the threads would be the cheaper alternative to replacing the head (or more then likely the whole engine or unit).
 
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Old 11-12-12, 04:41 PM
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I think I'd be reaching for the Helicoil kit.
 
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Old 11-12-12, 09:10 PM
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I'm with Dane. Reach for the helicoil kit or replace the head.
 
  #5  
Old 11-13-12, 06:00 AM
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Go to your local Automotive parts store and tell them that you need a Helicoil Kit for a spark plug. You are more than likely going to have to take the head off, but that is now biggey. Good luck with this
 
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Old 11-13-12, 06:21 AM
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I've even done it with the head in place by working very carefully and coating the drill and tap with grease to catch (hopefully) all the chips. On a small engine though it's so easy to remove the head I would go ahead and remove it and not worry about getting chips in the engine.
 
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Old 11-13-12, 01:11 PM
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Thanks!

Thanks all for your replies- I'll look into Helicoil.
 
  #8  
Old 11-13-12, 01:44 PM
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A little research into my RJ19LM spark plug says it has 14mm threads with 9.5mm (3/8") reach. McMaster Carr and some other places have M14 x 1.25 and M14 x 2 sizes offered. I'm guessing the M14 part is the internal thread size, which I'd need to match to the spark plug, but what is the "x 1.25" or "x 2" designation?
 
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Old 11-13-12, 04:58 PM
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The 1.25 (coarse) and 2 (fine) is the thread pitch. Hopefully Cheese or MowerDude will know for sure but I think the plug is 1.25 fine thread.
 
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Old 11-20-12, 12:04 PM
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I got hung up googling "RJ19LM thread pitch" and finally got the idea to look up the thread pitch for Bosch, NGK, and other compatibles. I'm going with 1.25, and looking for a thread repair kit now.

Thanks again~
 
  #11  
Old 11-20-12, 01:57 PM
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If you will go to your local parts store for automotive they should have a repair kit there, and yes that is the correct thread pitch. Good luck,,,,,,,you may even find it on E-bay.
 
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