4.3 Mercruiser suspected fuel pump?

[MrWhiggens]

I have a 4.3L 4 barrel on a 1994 Lund Baron. Just getting ready to do some fuel pump testing. The engine fires and runs for about 1 second then dies. Has fuel at the accelerator pump at each attempt. Any thing else I should be looking at before pulling the carb fuel line to check for fuel flow?