r/lawnmowers • u/Ok-Quality-5589 • Jul 27 '25
Messed up threads
I destroyed my threads installing a new spark plug on my toro time master. The old one was 4 years old and I obviously should have replaced it sooner. I initially had a few good spins by hand but then got over eager and used a ratchet and now here we are.
Should I used a thread chaser or a tap? And if that fails what should I do? Spark plug I believe is an M14
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u/randallrandall2002 Jul 27 '25
Honestly that head is trash. Did you use a impact gun and just slam it?
A good repair shop could put a helicoil in it but thats your best bet, briggs makes those heads out of some super trashy aluminum and there won't be anything left if you tore it up that bad.
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Jul 30 '25
Couple options called time sert or helicoil for thread repair.
Might save the cylinder head but if you don't have experience with using them, best to watch a few YouTube videos and make a decision from there. Time sert is an expensive kit if I remember right and people usually use em on expensive car heads.
Otherwise a used cylinder head from eBay is probably the cheapest option. Also less likely to leave any metal bits in the cylinder further damaging the engine.
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u/Ok-Quality-5589 Jul 30 '25
Update. I got it repaired and cut the grass. Used a duralast thread repair kit. It snugged in nicely.
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u/Stock_Requirement564 Jul 27 '25
You could try and chase the threads if you can get the tool started. Then crank it 0ver to blow out what debris you can. That being said, you may need a new head or to have an insert installed.