Carb (TKS) problem?
 

I recently bought a 06 Mariah with a Mercruiser 3.0 with TKS Carb. The engine and everything runs great when it is cold. When it gets hot it WILL NOT operate at idle speed. It will run at 50% + throttle but it will not run well or at all below 2000 rpms.
I checked the spark, compression, I cleaned the fuel system, changed plugs, distibutor cap and rotor, I pulled the carberator and cleaned it very well and everything apperared to be working well. Someone suggested I cut the shroud over the the Idle Air mixture screw so I could adjust it as they said it might be causing my problems. I ran it neutral at home and adjusted the idle and air mixture screw. It ran great both cold and hot and at low RPMS. I thought I had solved the problem whatever it was.
I took it out today and it ran great after I fine tuned the idle and idle air mixture screw in Drive. It ran like a champ for about an hour and a half. I turned it off several times and it started and idled perfect. Later I went to slow down and the engine stalled. After that, no matter what I did I could not get the engine to run below 1700 rpms. It would not start unless I immediately throttled it when starting. I would have to throttle it about about 75% to start it and it would not run below 50% throttle.
No matter what I adjust the boat will not idle. I assume it is a carb issue and maybe something to do with the TKS system and "enrichment module. At this point I would buy a new carb if I thought it would solve the problem. I am afraid I am missing something else though. Anyone have any advice?