Well there are plainly other factors at play. I remember taking the blade carrier off my dad's Waltons 160 FC with cup starter and it was tougher to pull but never any kick back. It felt like starting a scaled up whipper snipper.
I think it's just the way the PT is. Your mileage may vary.
It would be nice if you could figure out a way to modify them enough to stop the problem, but in the meanwhile a deliberately ginger pull of the rope or using a tired PT with less compression might help! They don't need to be as powerful with the 2:1 ratio of the belt driven Blade disc.
P.S : It could be the way t the PT starter engages on the conrod and remains locked on when the piston bounces back. The FC cup starter strictly engages one way, that is the starter pawls can't grip the cup when the motor moves the other direction from the piston bounce, whereas the PT starter continues to grip the bouncing engine whilst tension remains on the rope.
Last edited by Mowerfreak; 10/04/20 05:07 PM. Reason: Extra point added.
