Outboard motors have gained weight from the 1980 to 1990 era to the present day. For example, my 1985 115 HP Johnson weights 301 pounds. In comparison, the new Evinrude etecs weigh 390 pounds for the 115 HP V-4 and 418 pounds for the 150 V-6. That is huge weight increase that affects how the boat handles. Sure they are smoother running, quieter, and get better gas mileage, but the added weight means less responsiveness in turning and slower speeds. For our classic Glastrons, I prefer the looks of the old over the new.
In Mercurys case, the old 115 HP in-line 6's weighed about 312 pounds and Greggs 115 HP Mariner 326 pounds. The new Mercury 3 cylinder 115 Pro XS weights 375 pounds and the Mercury V-6 150 Pro XS 505 pounds. Mercury seems to be shy is disclosing the weight of their motors, either disclosing it in kilograms, or not stating it at all.