Re: Johnson PO-15 Spark Plugs?

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October 27, 2016 at 4:28 pm #46564
garry-in-michigan
Participant

    Spark plug "reach" is the distance it screws into the head. Using too short a reach will recess the contacts and may strip the threads in aluminum heads if over torqued. Too long may hit the piston, closing the gap, or worse. . . 😮