I just replaced the original Champion RJ19LM spark plug in my 97? 5.5HP Craftsman mower with the identical plug from HD for $1.99. Man, did it make a world of difference or what!
Previously, it took an average of 15 pulls to start the mower despite priming it per the instructions. The plug probably had 200+ mows (30 min each) over the course of nine or ten years.
Today, after the new plug, it only took four pulls
to start. I came back and tried to start it again after an hour, and it started on one pull!
Why didn't I do this sooner?
A little question though. How tight are you supposed to tighten the plug? I didn't have the correct sized socket so I used a small adjustable wrench. I wiped the threads clean on both the plug and the engine (a bit carelessly) and coated the plug threads with clean engine oil. Installed it by hand, then tightened with an adjustable wrench gently for another 1/2 turn or so. It seemed fairly tight, though if I really wanted to, I could've probably gone an additional 1/8 of a turn. Do I need to tighten it more?
Here's a picture of the old plug:
Previously, it took an average of 15 pulls to start the mower despite priming it per the instructions. The plug probably had 200+ mows (30 min each) over the course of nine or ten years.
Today, after the new plug, it only took four pulls
A little question though. How tight are you supposed to tighten the plug? I didn't have the correct sized socket so I used a small adjustable wrench. I wiped the threads clean on both the plug and the engine (a bit carelessly) and coated the plug threads with clean engine oil. Installed it by hand, then tightened with an adjustable wrench gently for another 1/2 turn or so. It seemed fairly tight, though if I really wanted to, I could've probably gone an additional 1/8 of a turn. Do I need to tighten it more?
Here's a picture of the old plug:
