Carburater adjustment only affects idle mixture. If you need to adjust the mixture when it's under power, you'll need to use an exhaust gas analyzer and change the jets and/or metering rods.
The only adjustment that you can lean out would be the idle circuit. That would be done by adjusting the idle mixture screw(s) while monitoring the vacuum and or the engine rpms. To make a carburetor run lean would require changing internal parts such as the jets and metering rods.
need to know how to make adgustment
Yes, if indeed it has a carburetor. Vehicles with carburetors have were phased out during the 1980's. The year, make, model and engine info would help.
Flow of fuel through the carburetor is controlled by the Throttle Position Sensor (TPS) - that would be the first thing to check before trying to make any adjustments.
The fuel/air adjustments on these carbs are factory sealed and cannot be adjusted. There have been many that have drilled these plugs out and attempted to make the adjustments but, I just can't recall anyone that was successful in performing this procedure. In the end, they had to have them replaced.
It depends what type of adjustment you are trying to make but you should refer to the manual if you have one. If not then ask someone at a shop to help you. For most tuning though there are little screws you can twist both on the carburetor itself and on the tubes leading into and out of it.
To adjust the choke on a 1978 350 4 barrel Chevy truck engine, turn the screw on the side of the carburetor. This screw is located in the side of the carburetor. Turning the screw to the right makes the choke open farther. Turn to the left to make the choke open less.
tillotson 2d series carburetor
If the engine runs well after it's warmed up, you just need to adjust the choke to make the engine start and run better when it's cold.
The 1987 Toyota Camry does not have a carburetor. It is fuel injected.
Usually a product of valve overlap and exhaust. It's basically unburnt fuel coming through and igniting on the hot exhuast tip when it hits the air at the end of the exhaust pipe. In aspirated cars it's large valve overlap which helps scavenging and performance in the top end. Turbo cars, due to the large amounts of fuel at full noise. Normally happens after high RMP then throttle snapped shut.
Several things could make a carburetor backfire. The engine could be out of time. the carburetor could have a stuck float, or the engine could have a stuck valve.