There needs to be 1/8 to 1/4 play between the lever and the "Body"....I would also check and see if your needle jet came loose inside the carb...i.e. the throttle plate popped loose and your needle jet is just "flapping". I had the same problem with an Indy 500 I bought used....turns out, the "Dumbo" attachd the throttle cable to the slide, then put the throttle plate on and THEN....dropped his needle jet in.....which resulted in the needle jet just floating and not doing its job.
2005 SKI-DOO GTX 550F
2000 POLARIS 700 RMK 159"
1994 POLARIS INDY 500 SKS EFI (Converted to carb)
1992 POLARIS INDY 500 SKS EFI (Converted to carb)
1991 POLARIS INDY 500 121" (Carb)