Purchase a rebuild kit. Take the carb off the engine. Disassemble the carb. Clean the parts with carb cleaner. Reassemble and install then adjust carb (if applicable) while running the engine.
Adjust carb on 400 Polaris 4x4 2stroke
"84 is still the carb. There is a small screw right at the throttle cable on the carb. Adjust that.
there is a screw on the carb. be sure to adjust while the engine is running so you can tell by the idle when it is set properly.
It is usually above the float in the little bowl at the bottom of the carb.
Check internet for book form 69590, this is techumsehs carb identification, troubleshoot, and service book. Very helpfull!
there is a set screw on the linkage on the carb that will adjust it.
it's the screw right above the mounting bolt on the left rear of the carb. you'll have to adjust the idle screw as well as you lean it out. then check your timing again
Adjust the throttle stop screw located on the side of the carb that has your throttle linkage connected to it.
adjustment screw is between throttlre linkage and carb body on the right side of the carb as you stand at the front of the car looking at the carb
with a screwdriver
twist the screw under the carb