How to fix stripped spark plug threads???

  • Profile photo of dave_ndave_n
    Champlin, MN
    Posts: 168

    The threads in the head of my snowblower are stripped from screwing in the spark plug cockeyed. It looks like only the top 2 or 3 threads are bad. Is there an easy fix? Any help is appreciated.


    Profile photo of muskymanmuskyman
    Arkansaw, Wisconsin
    Posts: 947

    A Tap and Die set is something every man should have.

    Rochester, Minnesota
    Posts: 1,240

    I dont know exactly what the tool is called, but i think its like a spark plug tap. it is a reverse tap. you put this tool in then screw it to fit snugly into the threads and then you slowly reverse it out of the spark plug hole, should regroove it. Otherwise you can heli coil it, that is just making the hole bigger and then putting a sleeve in it. Go to sears or napa they will have what you need.

    Profile photo of greg_rgreg_r
    Woodbury MN
    Posts: 231

    Sparkplug Chaser… Auto parts stores have them or you can use the correct size tap to fix the threads and if that does not do it you will need to heli coil it with a new thread insert.

    Profile photo of john23john23
    St. Paul, MN
    Posts: 1,792

    All good advice. Be careful to keep metal shavings out of the cylinder when you do whatever you choose to do. Lots of good tutorials online.

    Rochester, Mn
    Posts: 5,352


    Sparkplug Chaser… Auto parts stores have them

    That is the best way when just a few threads are messed up,Just go slow ,take your time and you will do just fine

    Profile photo of Todd GeerdesGeerdes
    Brandon, SD 57005
    Posts: 568

    Heli coil will work. I have used one before in a 360 aluminum head ASCS sprint car motor and never had a problem. Good Luck

    Somewhere over the rainbow
    Posts: 2,591

    Since you only have two or three threads messed up I would use a thread chaser. Just work the threads from the inside out. Your inner threads should be enough to allow you to tighten your plug. If all or most of the threads were marred then I would remove the head drill and install a heli-coil (sp?) Just take your time with the chaser.

    Profile photo of schweg2schweg2
    Posts: 100

    Put grease on the tap to help keep shavings out of the cylinder.

    Profile photo of dave_ndave_n
    Champlin, MN
    Posts: 168

    I finally got around to fixing the threads on my snowblower. You guys were right – I went with the thread chaser and it worked perfectly. Only cost me $6 at Sears. Many thanks again to everyone on the forum.


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