Engine slow is over 1100 RPM

Idle Speed - Carbureted Models

Turn lights and accessories off. Place transmission in Neutral and connect tachometer to engine. On models with Idle Speed Control (ISC), turn ignition switch on for.18 seconds, then turn ignition switch off and disconnect oxygen sensor and ISC terminals.
Start and warm engine to normal operating temperature. Perform adjustment with electric cooling fan disconnected, (if equipped). Run engine at 2000-3000 RPM for more than 5 seconds and return to idle for 2 minutes. Set idle speed by turning idle speed adjusting screw. See Fig. 3.
Fig. 3: Carburetor Idle Speed Adjusting Screw Locations
Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
On models with ISC, ensure mixture (CO level) is.1-.3%. Close idle speed screw until engine RPM increases. Open idle speed screw to point where engine RPM does not decrease. At this point, open idle speed screw 2/3 turn.
Accelerate engine a few times and return to idle. Ensure mixture and idle speed are properly adjusted. If not repeat step 3). Turn ignition off and reconnect wiring. On all models, check Throttle Position Switch (TPS) adjustment. See TPS ADJUSTMENT in this article.
On models with throttle opener, disconnect idle-up solenoid wiring harness and use a jumper wire to activate idle-up solenoid. With engine speed at 2000 RPM, open throttle slightly and then gradually close throttle. Adjust idle speed with throttle opener adjusting screw. See Fig. 3. Again open and close throttle slightly and recheck idle speed.