How fuel mixture full close then two or three turn open pl must reply

close the air screw in the carb totaly,then open it aprox 3 turns untill it idles smooth

most air mixture screws start off at one and a half turns to reset this turn all the way in to the stop them back out one and a half turns for your starting point . cheers pete

While engine is turned off.Screw shut both fuel and air mixture.Then each screw turn open 2 and half turn or some times 2 full turns.that should give close enough mixture .then switch engine on and make sure idle at 10rpm for auto and 6 rpm for manual.Then adjust screws lightly to your needs constant check rear exhaust for color of smoke if black it\'s too rich in fuel and if it\'s a farting noise coming out of the exhaust it\'s too lean.The sound out of the exhaust should be running continues and no missing.

There's a shutter valve to restrict air flow either before or after the air filter housing. In cold winter, this valve is closed as you start up the engine. As the engine area warms up, the shutter valve opens up to allow more air to flow into the intake manifold. In close position, the restriction in air flow results in rich fuel mixture. When its open, the fuel mixture is leaner. If it were locked in open position, you crank the cold engine and you get a lean mixture instead of a rich mixture to start up in cold mornings.

Replace the chock thermostat. When the engine is cold, the choke is in closed position to restrict airflow and give rich fuel mixture to combustion chamber. As engine area warms up, the choke thermostat gradually opens air passage to increase air flow to combustion chamber, resulting in leaner fuel mixture. The choke is in "full open" while the engine is cold, resulting in lean mixture, causing the engine to die unless you add more throttle to increase fuel mixture.

Good test. Do not keep doing that.
Make a new and accurate gas/oil mixture. Empty and refill. Secure cap. Be sure to flood system during start attempt. Can you smell gas? Oops, too much, better wait 30 seconds for full evaporation.
Two little screws near carb. Both are actually needles and probably have a visible spring which keeps them from vibrating to a new position while in use. One fuel/air mixture at low idle (start). One fuel/air mixture at high RPM.
Try 1 1/2 full turns open from fully closed. Once to get it to idle roughly, adjust to a smooth idle. Do the same at full throttle. You will notice that the more you shut the full throttle down, the higher the RPM will go (assuming that it is near correct). Do not run it to lean. The mechanics of the motor needs the oil from the gas.
Smile always.

the oxygen sensors trim and richen the fuel air mixture and they will not always set a code in obd1 vehicles. could be a stopped up cat though if the exaust smells like rotten eggs

I am going to make the following assumptions:
1. It is a Poulan PP4218(WeDoNotCare), start procedure the same.
2. You removed and verified there is spark (plug replacement recommended). The plug is dry (not flooded).
3. With the saw at waist height; the starter handle held; and the saw released. It remains against the starter handle or VERY slowly lowers with a distinctive pause during each compression stroke.

OM follows:
http://weborder.husqvarna.com/order_static/doc/NOUS/NOUS2004/NOUS2004_530165555-01.pdf
All Poulan CurrentModels
http://www.poulanpro.com/node4043.aspx
Type just the model numbers (choose the suffix after the list is provided).

It needs spark, fuel, and compression to run.
An overly rich mixture should not keep it from starting.
To much or to little fuel will (most start problems)!

The start procedures are on pages 9 and 10.
STARTING A COLD ENGINE
If the engine is cold - Please read the second NOTE: before trying to start.
If warm – read the DIFFICULT STARTING (or starting a flooded engine). I would try it with choke closed first (Pull to full choke; push to off choke). Hard starting is almost always flooded on a 2-cycle engine. You can prime all you like; priming does not inject the fuel mix into the carburetor. It circulates mix from the fuel tank through the carburetor and returns any excess to the tank.

If it never attempts to start and the plug is not wet.
1. Turn off the ignition.
2. Remove the air filter.
3. Pull the choke to full choke, push it fully open.
4. Put one teaspoon of fuel mix (40:1) into carburetor throat, reinstall air filter.
5 Turn on ignition.
6. Pull starter.
If it sputters or tries to start and dies there is a fuel delivery problem. Reply below with what you found and I will help repair that too.

I hope you found this helpful. If you have questions or need additional assistance you can reply below. Good Luck
Lou

Please reply below with what you found. Help me help others. TIA
Lou

You have disturb the setting of the air fuel mixture at the
carb. The air setting is located at the carb side. You can
reset this using a small flat screwdriver. Turn it full close
position clockwise. Then, open it turning counterclockwise by two and a half full turns. Then restart your saw, and then you can adjust this further
according to your desired setting.

Begin by screwing the mixture screw in all the way until it stopps,,,but ONLY JUST STOPS,,,,,DONT FORCE IT,,,then look at the top of the screw slot,,and call that 12 oclock,,,now turn the screw out to you three full turns going through 12oclock,,that means 12 to 12 is one turn.

then start the bike,,,finish your adjustments now by slowley turning the screw outwards until the engine starts to misfire,,,at this point turn the screw back in one half to three quarters of a turn.Now you have the mixture set roughly.
For fine tuning,, you need to use a monometer while turning the mixture screw
Best of luck...