I just bought a 7.5hp Mercury. The seller said it was a 1980. Now that I have looked for the serial number "plate" I find it is missing. In looking around the engine block I see "Ser. No. 12288", and the nos. 85847, 1092, 1019-7313, and 21596589. The carb. is a Mercarb carb. 1364-4929 which I understand indicates it is a Canadian motor. Can anyone tell me what year engine this is? Thanks