Need Info on my MERC BLACK MAX V6 mercury says they need my 8 digit serial# but my serial# only has 7digits?

Question

I bought a boat with this V-6 on the back problem is mercury's website says my engine serial # should be 8 digits but the I.D. plate with my serial # on it only has 7 digits I've repeatedly looked at the plate to see if a number or letter had been rubbed off or removed but the plate is in perfect condition I've been told the motor size is anywhere from a 150 horse up to a 225 horse motor The motor is black with white and blue markings that just say Mercury Black Max V-6 Power trim no model # or manufacture date anywhere Without this info I can't get parts or even use my repair guide PLEASE someone help

Answer 1

Serial#s on the late 80s V-6s were seven digits. What's the number?