So I've got a 20hp Merc that I've had idle and running issues ever since I've bought it but it has good compression on both cylinders and no scoring but #2 is not burning at idle and seems to be flooded. Replaced coils,wires, plugs and has good spark so I then checked reeds they seem to be in...
So I'm having the exact same issue with my 89 merc 20 horse and have checked all of the same things you had and so I took the power head off the lower and I have fuel puddled in areas but the seal looks ok but it might be put in backwards..which way does the bottom seal go in? My repair manual...