0.020 in or 0.50mm
Champion CJ8 spark plug is for the crsftsman 3.0 edger/trimmer
on most trimmers the gap is about 25 thousands !!
Champion RCJ-6Y ... per the Manual.
Spark Plug gap is .025
.030
.030 Champion RJ19LM
Champion RDJ7Y is the correct number.
.030
The compatible spark plug for the Troy-Bilt trimmer with part number 794-00050 is typically the Champion RCJ-6Y or the NGK BPR6ES. Always consult your owner’s manual or check with a local dealer to ensure compatibility with your specific model. Proper installation and maintenance of the spark plug can enhance the performance of your trimmer.
My 16" Craftsman 36 cc chainsaw manual calls out for a Champion RCJ7Y....if that is the same size chainsaw as yours, I would go with that plug.
Mine has original plug, it is a: Champion # CJ8Y
Spray some ether in the carb. If it fires, it has spark, but not getting fuel. start there.