1972 Mercury 80hp ??

I would like to ask a few questions.I rebuilt my original carbs and reinstalled them and started her up to see how she would run.Started up fine running in a tank. Adjusted the Idle mix screws to 1 1/2 turns out @ approx. 800 rpm.When I shut down the motor the top carb is showing vapor coming out, bottom carb no vapor.What causes that?? Bad Reeds?? On another note my compression on number one cylinder is down to about 110 and the rest are in the neighborhood of 125 psi. I see alot of parts on ebay in the 80/85 hp range can I use pistons,reeds,and crank from a 85hp model in my 80 hp block? I am thinking about honing my block out and putting good pistons and new rings and if needed new reeds.Whats interchangeable and what isnt concerning the inside guts?? Thanks guy's for any advise..

Re: 1972 Mercury 80hp ??

Your compression is fine. Normally reed valves are real reliable. A lot of parts are interchangeable, however, right now it doesn't sound like you need any.