throttle cable

i just put a new carb in froma junkyard and since idid this the cable that beside the throttle cable is way to tight and u can't adjust it either so my paps freind he works at whellers he said just disconnect because when i out it on i thinbk it is like the back up cable or soem thing it goes on tothe throttle thats all i knowand i have it disconnected and i canstill drive like that the gasand veerhtign works im just not getting nay power like up hils i go like 20mph lol but whrn i oputthe cable back on and i start the car the rpm's go up to 3-4 thousand which is not good and if i put my foot under the gasand lift it up the gas pedal i mean then the rpm drop so that cable is sticky for some reason ihad the car for 2 yrs never did this before til i outthe new carb in but the only thing i can think of is to buy that cab;e froma junk yard and try it well if u know why this is happeneing respond back asap