Hi Dave got the info on the 120 AC and again thank you very much , I fired it today and I don't think i'm getting what I should for RPM's around 79- 8100 using a 16x8 prop 20x20 YS fuel, Very sluggish to get top Revs .I did notice some fuel residue coming out from around the carb barrel, not alot but enough to see. This engine has a new head ass,ring,bearings, gaskets, o rings and a rebuilt regulator.Granted its not yet broken in so I would expect it to go up a few more turns ,but as compared to my other 120 's both SF's they crank the same prop at 92-9500, and its almost instant .One other thing I had to do was turn the reg out about 2 turns from flush and the needle is open approx 2 1/2 turns to run that good .It acts as though thats to much prop ,so just for kicks I dropped down to a 15x8 thats all I had on hand ,it ran like a YS then, instant acceleration and tached out at 93-9500.
Can you think of anything I may be missing here ,I doubled checked the cam timing& valve clearance just in case and it was fine I can't find or see any air leaks.This engine was taken down to the bare nothing cleaned spotless and all the ports was cleaned and inspected for any blockage,even the needle vale assy.
Is this all I am going to get out of this particular engine?
FYI just so you know I have rebuilt several of the 120 YS engines in the past but not a AC version and they have all come out great .
Any advice would be greatly appreciated.

How does it feel when it's hot? Does it have good hot compression? If not, that might be the problem.

Yes it feels as good as it does when its cold ,after doing some through checking of things I found my tank was not holding pressure ,I changed the tank out and got a nice supprise it now runs the 16x8 at 85-8600 which I can live with ,as I get some time on it I am sure it will go up some .I am still somewhat puzzled at why the regulator needs to be turned out that far ,but as long as it runs ok what the heck .Thanks for all your help and fast response ,its always a pleasure talking with you.

Well, we know YS's don't like leaky tanks. At least you found some problem.

Good Flying!