fuel line size ?

[westaustralian boater]

hi just looking at fuel line . i see there are two common sizes 5/16" and 3/8" .
i have a 50 hp blue band motor serial # 8056080.
what size should be used for fuel line on this motor . also if using 5/16" for fuel line would it stave the motor of fuel or is 5/16 ok for that size and 3/8 for larger motors?... just bit confusing whith 2 sizes fittings etc...

[boatmangc]

5/16 should be suffucient.