Its a very easy but useful test to make sure your spark plug is ok , you may need to clean the electrode to ensure you get a good reading but all you then have to do is set meter to read ohms and measure from the spark plug cap end to the electrode tip , and then from end to body to make sure no leakage to earth.
Sunday, 24 January 2021
How to test spark plug with multimeter to see if is it is good or bad
Get set up turn meter to ohms reading on dial and clean the electrode as below
Test between end of spark plug where HT lead cap fits and the tip of electrode the reading is very low only 1.2 ohms
on a dirty part of electrode the reading goes wild and eventually read 188.9 ohms so very bad and to avoid this clean electrode tip
Next test from spark plug cap end to the body to make sure no earth leakage your meter should read OL which is a good reading as it signals no leakage to earth via the body.
See video of this process below