Merc Powerhead age

[marshan162]

Can anyone answer this, the core plug at the top of my power head by #1 cylinder has stamped 198685. Is this part of a serial # or the age ie, 1986 Aug 5. BTW my transom bracket is not original and hence useless to determine the age.

Many thanks
Karl

[YELLOWSS]

a lot of the blocks have the # stamped where the front half meets the block on the port side at the top.
roy

[marshan162]

Thanks i'm off to have a look