I dont suppose those new ohv type engines have any adjustment screws on them do they? like under the carb bowl nut? or on the side, opposite of the fuel inlet? even if not, theres still things that need to be really cleaned out. obviously on the main jet holding the bowl on theres a hole or two there that needs to be really clean. and I think theres actually a secret jet, behind some plastic round piece where the idle adjustment needle used to be. theres a jet in there that you can unscrew. that thing has tiny holes that need to be blasted clean also! the engine will never run right if these parts aren't cleaned out good! this place shows that type of carb, and where all the holes and jets are.
Disassembly, Cleaning and Repair of Tecumseh Carb 640017