an rc8j resistor or a cj8y
You can use the following plugs for a cross reference for a Champion CJ8 Denso - W20M-U NGK - BM7A or BM6A (BM6A is a hotter plug than the BM7A) Bosch - WS9EC Autolite Part # 255
Cj8 is hotter than cj7
.30
Champion CJ8
Yes you can use a CJ8 for a CJ8Y, but you cannot use a CJ8Y for a CJ8......the CJ8Y has about 1/4in more thread.
Champion CJ8 spark plug is for the crsftsman 3.0 edger/trimmer
Champion CJ8 is most popular
on the back of the plug package it has : replaces CJ8, RCJ8, J19LM & RJ19LM. hope this helps.
It is a platinum version of the Champion CJ8.
Depending on the model, it could differ, but the most common would be the champion CJ8 spark plug, or similar, double check at your parts store before you buy.
If it is not written/stamped on the engine, and you don't know the model number of the mower, you could go by the spark plug itself. For instance, a Champion brand CJ8 spark plug is typically set to .030" Most mowers are either .025" or .030" so if you can't find it elsewhere, try one of those.
Mine has a cj8 in it, not 100% sure that og part though or what someone just put in it. works fine with it