Mercury 9.9 HP 2011 4 stroke - fuel / carb issue. Help!

I have a 9.9 hp mercury 4 stroke 2011. It will not start unless full choke and out of gear at medium rpm's. If, at those rpm's, I disengage the choke, it will die. While choked, if I then throttle down to idle to put in gear, it will die. If I do that very quickly and get back to high rpm and no choke, it runs just fine.

I dumped out old gas and got new, fuel filter seems fine, I took the fuel pump off and it seems to work fine so I put that back on. Is this a carburetor problem? If so, what specific part of the carb should I attack first? Help!

Pull carb. disassemble entirely,soak overnight,clean every nook and cranny thoroughly,blast all orifices with clean water,followed with dry compressed filtered air, Make sure jets are spotless. Check tank,lines,fuel pickup,etc. for contamination,gunk,water,rust