I have a '92 176 double eagle.  Has a 115 2-stroke on there now, no issues with weight or anything- tons of power.  I am flirting with repowering to 4-stroke though.  Would be a 90HP.  Phoned double eagle and they say 90% of their 176 boats that leave the factory are powered by 90's now, but he said they will  also go good with a 75HP and are rated for up to 150HP.  I figure 90HP is enough HP to get me where I need to go and I can troll off it easy enough should my kicker start acting up.