Old Outboard Book says – 6M
Old Outboard Book cross over chart says – K15J.
Internet search –
• Autolite 386
• Champion D14
• Champion D14013
• Motorcraft BTS8F4
• NGK 1010
• NGK 2910
• NGK A-6
• NGK AB-6
• NGK AB6
• NGK stk 2910
Tubs
A "Boathouse Repair" is one thats done without having tools or the skills to do it properly.