The fuel pump has no effect on starting the motor uses what is in the carb bowl already. If the fuel ball pumps up firm probably do not have a leak in the line.
Turn the throttle as far as it will go right away. Don't adjust it little by little. If your motor is sitting for more than 10 minutes you may need to cold start it.
I know, I know Your motor is more special than the other millions of them out there. Everything is different on your one motor so it requires a redesign, I get it.