Seagull serial number dating
AA3 = January 1973, BB3 = February 1973, and MM3 = December 1973.
Therefore identification of a model and date of manufacture can be found as follows: WSPCL 1734 BB3.
A3 = January 1963, B3 = February 1963, etc., and M3 = December 1963 (the letter L is not used in this code sequence).
From 1973 two letters were used in the code to indicate the month, i.e.
As I have seen this motor and it has the number 'O' instead, it looks as if a typist simply pressed the ')' instead of the '0', by hitting shift at the same time.
The use of the number '0' in all the previous models tends to bear this out.
Need to look through a few hundred crankcases to figure this one out.... I will create a special page just for the Marstons and transfer all the info on them to it.
his research has added another letter to a few of the motors. The FVP and FV motors had the factory option for a while, of a lifting or pivoting tiller. they did not do it for long as it was not a very useful exercise, after all you could see the darn thing had a wipac if you looked at it and you did not know what month it was built...
the engine was suffixed with a 'T' and a bent bracket fixed to the crankcase, to pivot the tiller on. I have found several of these now and had a dozen or more reported to me, but recently I turned up another upside down 'M' so you have to look carefuly!
The above table is still not 100% as the letters N were not used every year, December being M, so one can assume another letter was used somewhere.
As it was not supposed to be 'L', that only leaves 'I'.