*Another learning opportunity so bear with me.
How does the carbon buildup make it "kick" harder? Does it affect the timing or somehow make it fire hotter?
The first Shindaiwa 500 I had was very hard on the hands if I wasn't paying attention and went easy on the pull. Very surprising as it is a smaller saw. I've had over 50 other Shindaiwas without issues but recently resurrected another 500 with the same issue.
Sent from my iPhone using Tapatalk
Carbon buildup displaces the volume of the combustion chamber, which raises the compression, which makes pull rope harder to pull.
However to further answer your question, the higher compression leads to possible preignition problems. The fuel exploding before the piston gets to the top is the kick you feel.