I have a mitsubishi 1990 model w/ 4g15 engine. i replaced the original carburetor w/ the 3k carburetor of toyota. the problem is that the power seems to decrease. the idling of the engine is low in the morning.

SOURCE: I found my engine Mitsubishi pajero fieldmaster

unsure if this is petrol or diesel model. check basics first,air filter not clogged,sparkplugs not sooted and gaps burnt wide. if it is a GDI V6 model,thay have common fault with dirty throttle body(TB) and air mass unit,causes rough idle and gets worse over weeks until it doesnt improve.this can be easily fixed by cleaning with solvents available for air flow sensors and tb's. if engine has plastic cover,remove this to access TB

SOURCE: Carburetor Tuning Mitsubish.

As far as i know, original stock carburetor for Lancer 1989-1992 engine 4G15 12 valve is Aisan Variable Venturi. It have 3 screws :
- air-fuel mixture screw
- main jet adjusting screw
- idle adjusting screw

and here's the document you may need :
http://www.mitsubishi-motors.kiev.ua/info.php?id=20
http://www.lilevo.com/mirage/

Good luck !
Winz

SOURCE: My 1994 Mitsubishi Lancer (4g15) engine stops

Fuel pump

Testimonial: "It's the fuel pump indeed. Also the gas tank found to be very dirty. The fuel pump was replaced, fuel system cleaned, now the car runs perfectly."

Navin Sharma

• 315 Answers
• Posted on Jul 22, 2011

SOURCE: my car is mit. lancer

Check the idle control valve

SOURCE: 1998 ck2a lancer 4g15 no go. have replaced dizzy, computer and tps. has spark and injector pulse and timing is fine. any help appreciated

the next thing to check is the fuel system.
is there fuel in the system, the tank, fuel lines. is there fuel pressure at the injectors? check the fuel pump electrical system, the fuse, fuel pump relay, fuel cut off circuit. some factory security system have a fuel inhibitor, that disable the fuel pump circuit!