1980-2 dt40 fuel issue

[Just Me]

Well after sorting out the motor with a new thermostat and impeller all was well till....i took it out for a decent run and noticed the motor felt like it would die then pick up again.
Once home i ran it on the muffs till the engine died, pumped the primer again and same thing. Just incase the primer was faulty i replaced it with a new one and new fuel line plus new spark plugs. I'm suspicious that it may be the fuel pump. What should i look for? The diaphram? Is there a way to test the pump?
Any ideas or thoughts.

[boats.net]

Definately sounds like a fuel pump. You can disconnect the out put hose on the fuel pump and turn it over. If it pumps a good amount of fuel with pressure, then not likely the fuel pump.