sucks dude...
i had a not-so-fun problem like that myself... borrowed a compression tester which had an extended reach adaprer you threaded on to it. well, little did i know at the time, the adapter was stripped as s***, so when i went to pull it out, the whole thing just spun.
well, after about 1.5 hrs of playing with it and tugging at it, i finally got the adapter off the main connector, leaving the adapter stuck in my spark plug hole... two hours later, after removing the valve cover and gripping the inside threads with tape wrapped needlenose pliers, i finally got it unthreaded from the plug hole, and 20 mins later i had it out. worst 4 hours i ever spent on a compression test.
moral of the story: THOROUGHLY inspect any borrowed tools, especially if you get them from an auto parts store. and dont use their POS compression tester.
i had a not-so-fun problem like that myself... borrowed a compression tester which had an extended reach adaprer you threaded on to it. well, little did i know at the time, the adapter was stripped as s***, so when i went to pull it out, the whole thing just spun.
well, after about 1.5 hrs of playing with it and tugging at it, i finally got the adapter off the main connector, leaving the adapter stuck in my spark plug hole... two hours later, after removing the valve cover and gripping the inside threads with tape wrapped needlenose pliers, i finally got it unthreaded from the plug hole, and 20 mins later i had it out. worst 4 hours i ever spent on a compression test.
moral of the story: THOROUGHLY inspect any borrowed tools, especially if you get them from an auto parts store. and dont use their POS compression tester.