Change from mechanical to electric fuel pump

Have not installed the pump you mention but you need to add features to convert to an electric fuel pump.
Electric pumps need to be wired with an automatic shut off for safety.
If the engine does not start or if the engine shuts off the electric pump needs to shut down. Most of the safety switches give you a 3 second lead time, the pump runs 3 seconds and if it does not detect a running engine it shuts the pump off. Your choice of a Marine design is very good since any open spark can ignite fuel. Marine pumps would be shielded to avoid this happening.
In practice on older applications a mechanical pump is much more reliable and safer in a boat application. They are also quieter than an electric pump. My 95 Nautique uses two OEM electric pumps, they work but you hear them working. Hope this helps.