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
i put a header and a weber carb on mine feels like it doubled the hp
Weber makes an aftermarket filter for the weber carb,and K&N makes an aftermarket air filter for the stock carb
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.
Adjust or rebuild carb.
There is a single idle mixture screw on top of the carb, if there isn't much change and still running rough, you'll need to re-jet. Try .55-.60 idle jet, worked well for mine. Ordered 170 mains waiting to put in and test.
Canned carb cleaner but you will need new gaskets and should get a book that way you can adjust the float(s), linkages, etc.
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.
Weber 48mm IDA 40mm venturi-561 per carb Weber 48mm IDA 42mm venturi-583 per carb
well this is most likely a carb problem, but don't rule out a loose wire. for the carb. Try setting the float bowl levels on the carb. If that doesn't work your best bet is to replace the stock carb with a Weber or sidedraft. The stock samurai carbs are junk even if you buy a new one they just don't work that good. for a wire problem check you cap and rotor and make sure there is no cracks. check the coil wire and make sure you have good contact.
You're running way rich. Adjust your carb's mixture screws.
if it's a carb. adjust your idle screw out.
Adjust carb on 400 Polaris 4x4 2stroke