1993 50HP Evinrude - Fuel pump is missing a screw, trying to find size

[EricJRW]

Model VE50TLETF

A housing screw (at the top) was removed in order to attach the pump to the air silencer. I'd like to replace the screw, and use the proper mounting holes (at the bottom).

Anyone know what size screw will work? The boat is 60 miles away and if I can buy this before I get there I can save some running around.

Note: This motor had its VRO removed and this fuel pump installed. The pump has a third line for the pulse, i.e. this pump is not mounted to the crankcase.

Attached are a couple of pictures. Notice the great mounting job in the second photo. Since the top hole is used for mounting, it does not sit flush. If I can mount via the bottom holes it will sit better too.