your stop solenoid isn't working, find it and manually pull on the linkage for the fuel dump attached to it (stbd side of engine by the fuel pump), plan on replacing the soleniod, the
wiring or the push button as one of these is the problem
if problem is that the stop solenoid isn't energizing, it won't stop you from restarting the engine later
Check your engine panel push button to see if works, if it does check that the solenoid energizes
I've recently replaced both of my engine push buttons and your boat is older than mine