special tool 09911-78730 what is it how to buy one

[MoonGlow II]

Hello new member here. just bought a new/used boat motor and trailer The motor is a 2000 DT150 with a seized cylinder. Paid $750.00 for the whole package and new the motor had issues so trying to fix it before repowering...found out need a special tool 09911-78730 to remove some of the cylinder bolts or at least to reassemble it any help thanks
ok just found out it is discontinued

[boats.net]

It's a 8MM hex wrench, it's no longer available.