Spark Plug Hole Head Thread Problem

[boatmon345]

Rebuilding 1997 Yamaha 150HP 2 stroke Saltwater Series II S150TXRV powerhead.<br />( Click here to view updated blog with new pictures )<br /><br />The hole for the spark plug on the head where shavings of blown bearings were spit through has a problem. Head is still off the block.<br /><br />When I try to insert a spark plug into the head, the plug gets half way and jams. If I insert the plug into the piston side of the head, the plug goes all the way in. This holds true for 3 plugs I tested with. <br /><br />I suspect metal particles are in the grooves of the head plug hole, but I have used a small flat blade screwdriver to run the thread and still have this problem.<br /><br />HELP. thanks.

 

[Texasmark]

Re: Spark Plug Hole Head Thread Problem

Get a tap and run it through. Take a spark plug to an industrial supply store and get a tap with those threads. <br /><br />Mark

 

[rodbolt]

Re: Spark Plug Hole Head Thread Problem

they make thread chasing taps for spark plugs, any auto parts store should have one.

 

[boatmon345]

Re: Spark Plug Hole Head Thread Problem

Thanks guys, went to the autoparts store and fixed it right up.