I haven't been able to identify the year. I thought it was 1975 because that year head gasket fit. Until I pulled the piston.What book? Clymer/Seloc ?? they're famous for
not having the right info?
Any more #s on the tag inside the bottom cowl?
Your motor might be a 1969 model and the older
ones used 3 rings.
ThanksAs jerryjerry says the older 55Hp btw. also the 35Hp and 45Hp had 3 rings.
I think about prior 1973-74 they had 3 rings.
The head gasket was the same for a long time and you can not identify the year by what head gasket fits.
To verify the year you need the model number, the serial number is just a serial number of the model number. 5551 looks like it is a 1968-69 year model.
I'll have a look. Have you ever changed one piston without splitting the case?Look on the block for a foundry stamp.
Under the power pack , maybe the coils or
on the bottom of the intake manifold? there
might be a foundry stamp.
Usually a circle with a smaller circle that has
a number in it.
That number is the year the foundry produced
the block.