1989 Johnson 15 JRLCEC. I'd like to convert to electric start and add battery charging capability. New parts about $580.00 former and $85 latter. Too spendy for me. I'd like to go used. Should I search for a complete "assembly" or try to piece it together wherever I find individual components? OR, would I be better off swapping mine for one that"s already "electrified" ?