For a Nikon FE, if you can continue to crank after you already cranked the shutter once, here is the simple fix.
Open the bottom cover, bend the flat lever/stopper downwards carefully (Don’t Break Anything), so it fit in the groove/notch to the circular metal disc its touching. You’re done.
The circular metal disc rotate while you crank the film advance lever. The flat lever is supposed to snapped in the notch securely after you cranked it (thus rotating the metal disc for the lever to lock in to the notch) to prevent further advances.