That is the case! If the motor is loose, it has to be tightened. Period.
I have a 40-690 and if the motor was loose. I would take it apart and tighten it.
It is easy, just takes an 1/2 hour to disassemble.
I'm asssuming the 40-694 is similar
Take the table off by unscrewing the screw on the front. (Heavy, don't bend screw)
Remove the nut in the back that secures the saw to the bench.
Now all you need is a star bit, 1/4" and 1/2" box wrench.
Remove attached light
Power Switch Cover -- remove 4 screws (remove cover later).
Remove the 'U' clip screw that the table mounted to, Slip off the U clip.
Remove the two screws require 1/4" wrench ( External nuts visable on outside)
Remove the two screws on the front bottom that secures the saw to the bench.
Lift the saw off the bench and lay it on its side with the motor off the table. (No weight on the motor).
Remove the rest of the screws. (one screw is longer than the rest, some have washers (make note).
Remove Arm Plate and switch cover.
The back cover (opposite motor) has tight fit, work loose slowly.
check and tighten motor screws.
Re-apply or add grease where there was grease.
There is metal plate 1 1/2" x 1 1/4" (approx) you need to align to put back cover on.
Also insure you do not crimp wires when you put cover on
The last screws are the ones that attach saw to bench, then the nut on the back.