Ok, here's some clarification:


Look at the last three letters of the model number. Disregard the very last letter (for year id purposes). The 70 hp leaves you with CR which according to the info above (which is correct) means it's an '84.


Your 90 hp is an exception. The letter "A" was a designation for an alternate color scheme (it was used during the late 80's and early 90's) and this info is not well known. I believe that the 90 hp is a 1989 model.


-John