Do not use ATF period.
Kim has already stated the flywheel nut torque value in post #7.
Did you replace your fuel lines when you rebuilt the carb/s? Water is the big concern as the water will absorb the ethanol out of the fuel and lower
I have a 2005 2.5 200 carb with a toasted piston. I bought a new merc factory 2.5 carb, but it has different style heads. Will this still work on my lower