If the engine stop dead like you have turned off the mower when you turn the blades on then you have an electrical problem.
If it stops dead like you kit a brick wall then you have a deck problem.
Slip the belt off the engine then try again.
Motor keeps on running then the deck needs a look at
Motor stops the same then the electrics need attention.
Not sure what a 7180 actually is so a photo or two would not go astray.