the mercury motors usually have a serial number on the motor, mine reads 45 JET whick is actually a 60 HP mercury...look on the motor blosk and there should be a round spot on it somewhere that has a series of letters and numbers, this is your serial number and if you enter that in to a website that tells you what motor that number matches youre in business...the actual motor HP is about 30% less with an outboard jet lower unit
my mariner was a 60 hp powerhead and the sn said so. new yamaha is a factory jet and still shows powerhead hp on model sticker and sn, badges on both showed the jet hp rating. if u say have a 60/40 its 40 jet horse 90/65 is 65 hp. now what hp does ur fish and game go by is the real question
the Mercury Jet power ratings are with the jet, well at least for their outboard models. I have the 40 HP outboard jet, which is based on the 60 HP power head