Re: Starting a Chevy 350 1976 engine.
Yes and no, if the boat has not been started in awhile you need to crank it over a bit so that the mechanical fuel pump can build fuel pressure otherwise your just working your arm out for nothing. If once the boat has been run you still need to dump some gas in the motor it can be a sign of air getting in the carb or fuel lines so it can be a sign of some maintenance needed to the fuel system, carb rebuild, new fuel lines etc.
Pumping the accelerator is in no way a bad thing other then if you pump it 10 times you can flood it but 2 or 3 times just helps the carb do what it should do anyway once you crank the motor, spray fuel into the motor.
Try not doing it, if the motor cranks 2 or 3 times before firing then maybe spray some starting fluid(a little not alot) around the carb while the motor is running, if the motor surges when you spray around the carb in a particular spot you have an air leak and that needs fixed. If not then don't worry about it.
I would consider it normal for you to have to pump the accelerator a few times to begin the season or even the first time that weekend on a carb motor. But if you have to do it regularly over the boating weekend it could mean you need to give her a look...