When warm looses idle speed and cuts when coasting to a stop

Someplace near the carburetor should be an idle mix screw and an idle speed screw. There may also be a high-speed mix screw. Try turning the idle speed screw in 1/4-turn at a time until it idles. If you turn it too far, the clutch will always be engaged so the blade will never stop.

Once you get it to idle, adjust the idle mix screw in or out 1/4-turn at a time until it idles at the highest speed. Turn the mix screw in JUST until the idle speed starts to drop a little, then back it out 1/4 turn.

Now adjust the idle speed screw again until it idles smoothly at a low enough speed that the blade stops.

There are several things you can do. Make sure the engine is in good tune, replace the air filter, Air the tires up to 34 pounds air pressure to lessen the rolling resistance, How you drive is most important. Take off from traffic light and stop signs slowly. accelerate steady, don't be in a hurry to reach cruising speed, unless, of course, you are merging with fast traffic. Anticipate stops. Start slowing down sooner when coming to a stop sign or traffic signal. Coast on the downhill streets, and use the cruise control as much as possible. Don't waste gas warming up your vehicle in cold weather. It will warm up quickly while you are driving. Any time spent idling is zero miles per gallon.

You didn' t list the model number. Have you tried placing the head on the grass? does it stop then? It has a centrifugal clutch, if the idle speed is too fast, it will spin. There could be a broken spring or dirt in the clutch keeping it engaged.

Find the EGR valve on the intake and locate the vacuum hose that is connected to it. Start the engine cold and as it warms up, pull the hose off and if it idles and drives fine, the EGR valve is bad and needs to be replaced. Please rate me on this answer.

it is not how many miles but the type of driving.

here is a OBD2 drive cycle test.

Generic OBD II "Drive Cycle" Most OBD II ("On-Board Diagnostics II") diagnostic monitors will run at some time during normal operation of the vehicle.
However, to satisy all of the different Trip enable criteria and run all of the OBD II diagnostic monitors, the vehicle must be driven under a variety of conditions. The following drive cycle will (theoretically) allow all monitors to run on (??) vehicle. (Note: Drive cycle specifics vary by vehicle!)

1. Ensure that the fuel tank is between 1/4 and 3/4 full.
2. Start cold (below 86°F /30°C) and warm up until engine coolant temperature is at least 160° F (typically requires at least one minute; up to 3 minutes).
3. Accelerate to 40-55 MPH at 25% throttle and maintain speed for five minutes.
4. Decelerate without using the brake (coast down) to 20 MPH or less, then stop the vehicle. Allow the engine to idle for 10 seconds, turn the key off, and wait one minute.
5. Restart and accelerate to 40-55 MPH at 25% throttle and maintain speed for two minutes.
6. Decelerate with using the brake [or the clutch!] by coasting down to 20 MPH or less, then stop the vehicle. Allow the engine to idle for 10 seconds, turn the key off, and wait one minute.

1 Inspect Spark Plug Incorrectly Gapped or Fouled Spark Plug(s). 2 Inspect Throttle Position Sensor Faulty or Incorrectly Adjusted/Connected Throttle Position Sensor. 3 Inspect Idle Air Control Valve Damaged, Loose, or Faulty Idle Air Control Valve. 4 Inspect Idle Speed Actuator Damaged, Loose, or Faulty Idle Speed Actuator. 5 Inspect Idle Stop Solenoid Damaged, Loose, or Faulty Idle Stop Solenoid

Does saw try to run? Initial settings are about two turns out from CW stop. Set high speed (on warmed up engine) to 4-stroke with no load, but smooths out with light load (cutting wood). Idle is set for fairly smooth idle, but engine picks up with throttle without lag. Idle speed setting is somewhat below chain drive clutch pickup, but allows engine to keep running.

Have you checked all the vacuum pipes around the top of the engine.?
It`s not losing oil pressure, it`s just about to stall when the oil light comes on.
Listen for a hissing noise under the hood.
Vacuum leaks can cause real problems with the inlet manifold pressures.
Good luck.

Hi Guest,
My name is Dennis and I also have the model you are having difficulty with and I can only repeat the instructions from the owners manual (with personal comments) because they have always served me adequately I hope that will serve your needs.
IDLE ADJUSTMENTS:
There are three adjustment screws on the carburetor labeled
H (for High speed MIXTURE)
L (for low speed MIXTURE)
T (for idle SPEED SETTING)
They are located just above the primer bulb. If your saw floods so soon in the starting process the idle mixture setting can be set too rich and the speed may be set too slow. Remember the chain will not move when the idle speed is set correctly with a WARM ENGINE!
Adjust the idle speed to just below chain movement WITH A WARM ENGINE this is just below the activation RPM of the centrifugal clutch. Let the engine run at a higher speed than idle until it is warm -- 3 min -- you may have to keep goosing it until then.
Please don't exceed the limits of the plastic limiters when making adjustments.
If you haven't adjusted the mixture screws you may just have to adjust the idle speed and that can start my turning that screw all the way in to the stop and then back out 4-1/2 turns for a good place to start. FAST IDLE -- Adjust the speed until the engine runs with out the chain moveing. Adjust clockwise to increase speed. Cclockwise to decrease engine speed.
Accelerate the engine and if it stumbles and makes too much smoke it's too rich turn the LOW SPEED MIXTURE (in) clockwist in 1/16 a turn incriments NO MORE at a time because a twocycle needs to run at a setting foe a short time to realy prove the setting. dont run it wide open to warm it up but it should be at a fast idle. Nothing you do will be proven correct untill the engine is warm.
Good Luck
Glad to be of assistance - please rate the solution because I will learn from your rating. Thank you
Your IDLE MIXTURE may be too rich causing the engine to flood.