The Mark VII uses a different speed control assembly than the Mark 5/V. Is the cam engaged to the sheave control assembly at the back of the idler shaft? Is there proper tension on the spring for the sheaves on the motor shaft?
Below is the speed control assembly for the Mark VII.
Mark V 520 S/N 09-11-01 completely upgraded to Mark 7, with all SPT's & more.
Model 10ER S/N R64000 first one I restored on bench w/ Shopsmith metal ends & retractable casters. Has Speed Changer, Model 4E Jointer, Jig Saw with lamp, a complete set of original accessories & much more.
Model 10E S/N 1077 oldest one I have restored. On bench w/ Shopsmith metal ends & retractable casters.