Thanks for replying.
The trans is getting power via belt, i don't believe the issue is with linkage or tension.
With the snowblower on wood blocks, wheels raised off the ground, wheels barely spin and will stop spinning when slight pressure from hand is applied to either wheel.
Belt to trans unit is properly adjusted.
I also disconnected control rod to manually move the lever that is connected to trans unit to rule out adjustment issues.
i hope that clears up what i am trying to describe.
The speed control rod could be out of adjustment. The turnbuckle to Shift Yoke length could be out. <--correctly set.
The drive engagement cable could be out of adjustment. <-- It is not.
Are the wheel locks engaged? <-- Yes.
Drive belt pinched by guides? Upper guide has 1/16 clearance, lower guide 3/16. <-- No, nothing is pinched. I believe the problem lies within the trans unit.
Can’t tell from the drawings just how the hydro unit gets engaged. <-- Lever on right side for forward and reverse, left handle engages trans drive belt.
It looks like Control Arm Extension would be the engagement and I think a cable going to the top of the hydro block for speed adjust. <--correctly stated.
Check both to see if the dash controls are moving the parts on the hydro. <-- They do.