Quote Originally Posted by pennyman1 View Post
For it to run well with the screw all the way in means the jets are way out of size for the motor. Best get one with the right jets in it that is new, then rejet the other one later.
Probably jetted for a 2.0, it will struggle all the way through the rpm range. The primary jets are the critical fuel supply point. Look at the plugs, they should tell you how lean it has been running.