Looking at the service manual it appears this motor has electric fuel pump.
Depending on the layout of your boat and fuel distribution constraints, maybe it needs some help. My 2 strokes have fuel pumps too but you have to get the fuel within the operating range of the pumps and that is the problem with first starts. I didn't change anything in the engine, just ensured fuel was available where the fuel pump could put it where it belonged.
In my engines that meant fill the carb bowls. On fuel injected engines, I'd imagine that would mean an ample of fuel at the inlet to the injection pump so that it would have something to pump. On an automobile engine the fuel pump is in the tank and it pressurizes the injection engine mounted "rail" to around 40 psi to have adequate fuel ready for the injectors to inject.
I know nothing about outboard fuel injected engines. I would assume that they have a squeeze bulb feed like the carb'd versions to get adequate fuel in the line from the tank to the inlet of the engine's fuel injectors and once the engine lights off the engine's fuel pump has enough suction to keep the flow moving. With the inline fuel pump the engine's pump doesn't have to work as hard.
I used an inline fuel pump on a boat that I had with a complicated fuel delivery layout. If I accelerated to full RPM (which was a little over the upper RPM max rating, 50 MPH boat, after a few seconds, the engine would loose RPMs. I wound up putting a pump in the fuel line and never had that problem again.....engine was new so it wasn't a faulty diaphragm problem.
