The serial number was on a plate riveted to the swivel
bracket above and between the clamp screws..
Serial numbers 3816308 thru 4140999 were 1974 models.
Serial numbers
4141000
thru 4357639 were 1975 models.
Serial numbers 4357640 thru 4576236 were 1976 models.
1974-76 Merc 500's were produced in Merc 500M (Manual Starting, Short Shaft,) Merc
500ML (Manual Starting, Long Shaft,) Merc 500E (Electric Starting, Short Shaft, with Alternator) and Merc
500EL (Electric Starting, Long Shaft, with Alternator)
This information has been provided as a courtesy by Bob Grubb and Grubb's
Marine. It is intended for personal use only. Copying and distributing of this
information for any other purpose is strictly forbidden without the prior
written consent of the author.