Okay here's my whole story I had a CNS carb on and I pulled the vent tube off It ran decent but the throttle cable broke,Well I order a NT carb and a new throttle cable separate,so I put the new cable and the nt on and it idle real high and the throttle would turn but not right.I got tired of ****ing with it.so I put the cns back on and it starts and get so high idle same as the nt.Okay what to do air leak or throttle to cable too long or to short....I just don't think it a air leak really think the cable is too long or short,because it does it on booth carbs.....please tell some good news