Crofter
Addicted to ArboristSite
It is ONLY centrifugal force that supplies the pressure to keep the clutch engaged. If you force the rpm down you greatly decrease the amount of torqe it will transmit and it starts to slip. That displacement of saw will not take much pushing on wood over 6" diameter. You could have a defective clutch, but it seems more likely you are horsing it a bit too hard. Let us know.
Frank
Frank