A while back I had same problems with a 90hp Merc.
Id have to re-prime the bulb, and then it re-start and take right off. Ran fine at faster than "no wake" speed to wide open.
Had fuel pump and some check balls in carb replaced. Never did it again. ran fine.
You might start with changing the primer bulb. And depending on how old it is, you might consider replacing the fuel line too. They bot are easy and rather inexpensive. There's some sort of diaphragm like thing in the primer bulb to prevent gas from draining back into tank when shut off.
I know others will help too, but good luck !
