Sublime....... ridiculous!
(Well, in as much as you could describe a blue band as sublime!
)
All joking aside, The first port of call should be the maker's plate on the transom. It will (or should, assuming your boat isn't too old) have a Max HP & weight written on it. Older ones will sometrimes give a max HP, but no weight, however if it's that old and you stick to a 2- stroke of a similar vintage you should be OK.