Blade shaft slipping - Skil 7 1/4" Magnesium "Mag 77" Wormdrive Saw With Twist Lock Model # SHD77M 72

It could be a number of issues. These saws have a built in vari-torque clutch used to prevent kickbacks. Basically, when the blade binds while cutting, the arbor spins but the blade won't (prevents kick-back). It works by not over tightening the blade washer (this is the slip clutch), if you over tighten, the blade washer can't prevent kick-backs because it has no room to slip, if you under tighten, the arbor spins, but the blade won't. I'd try to tighten the blade washer 1/8 turn and see what that does. If your actual arbor shaft is not spinning, you could have a gear issue. If you hear the motor running and the arbor slips (not the slip clutch) sounds like there might be a gear issue,If the rotor is spinning (the part inside the stator-i.e. the electric motor section) but it is not transfering that movement to the arbor, it has to be a gear issue.