Re: convert to electric start?
It is posible. the cheapest way would be to buy another 7.5hp motor or a 9.8 with electric start and transfer the components. I believe the starter is NLA. the cost will be about $500 if you can find the parts new.
Starter, Retifier, charging system, etc.
go to this site,
Mercury Marine go to parts express, look up your serial number, then proceed to look for parts.