My stihl chain saw runs full out without pulling the trigger? what can i do?

There are several conditions and situations that this can occur, but let's try the most common. This is also for any STIHL saw that was manufactured before 2014, after that, the M-Tronic saws have a different starting method.
Normally this happens when the engine fired and it was not audible, and the rope has continued to be pulled with the choke on.
This method is approved, but EXTREME caution should be used, and the CHAIN BRAKE must be used.
CAUTION: Do NOT use the drop start method, this is not an approved starting method under any circumstance!
1) Place the saw on the ground that is clear of debris.
2) Set the Chain Brake
b) place the toe of your right shoe thru the rear handle,
c) support the saw top handle with your left hand,
d) pull the recoil with your right hand.
3) Make sure the choke is NOT applied, place the master control lever in the start position (one notch above the choke position)
NOTE: at this point, it helps if a second person can hold the throttle at the full or wide open position.
4) Make 6 rapid pulls (a few more may be required), you should hear the saw start to sputter, keep the throttle open until enough rpm is obtained that YOU the Operator can gain control of the throttle (the other person stands aside now in a safe position) and remove the chain brake. Keep the throttle open until the saw starts to run properly.
*NOTE 2: The chain brake is designed to not only stop the chain in case of 'kick back', but also is to be used in starting the saw until you have time to gain full operational control of the saw. However, extended rpms above clutch engagement can damage the brake band, overheat the drum bearing, damage the clutch shoes and clutch drum.

I’m happy to assist further over the phone at https://www.6ya.com/expert/rolandw_c013176d62ee17ae

Starting procedure for Stihl.
(cold starting)

Place cutoff saw on floor (flat clear surface).
Hold throttle in, while pushing on switch all the way down.
Hold cutoff saw firmly.
Pull starter handle until saw fires, it should then cut out.
Click the starter switch up 1 click to half choke.
Pull starter handle again until cutoff saw fires up. note: it will be reving because the trigger is loched on, (blip the throttle once) and it should go to tick over.

There should be np need to keep playing with the choke when the saw is warm. No need to lock the trigger when starting warm..

1. Make sure dead mans handle is fully depressed
2. Squeeze throttle in
3. Push choke switch all the way down
4. Pull saw over till it fires
5. Click choke switch up one position to half choke
6. Pull over saw until it fires up, saw should start running at high rev's
7 .'blip' throttle for saw to return to tick over.

If the choke switch doesn't stay down in section '3' check chokelinkage to carb.

more information please..

To lock the choke on:-
1. depress dead mans trigget on top of back handle
2. squeeze throttle trigger fully in.
3. slide on switch fully down to 'full choke' position. 'it should stay there'.
4. Pull saw over until it fires once.
5. click 'on' switch up one position to 'half choke'
6. pull saw over again, saw should start running and be revving high.
7. 'blip' throttle, saw should stop revving and run on tick over.

Starting procedure for Stihl.
(cold starting)

Place saw on floor (flat clear surface).
Make sure chain break is on.
Hold throttle in, while pushing on switch all the way down.
Place right foot in the flat of the rear handle.
Place left hand on top handle.
Pull starter handle until saw fires, it should then cut out.
Click the starter switch up 1 click to half choke.
Pull starter handle again untilsawfires up. note: it will be reving because the trigger is loched on, (blip the throttle once) and it should go to tick over.

There should be np need to keep playing with the choke when the saw is warm. No need to lock the trigger when starting warm.

Warm starting is performed by holding the rear handle between the thighs rather than on the floor.

Set choke to full on. To do this depress throttle all the way down and set choke lever to on. Pull starter rapidly until saw fires . Once it has fired set to start and pull starter cord until it starts. If it doesn't start in ten - twelve pulls,reset choke for two or three pulls,then switch back to start. Pull starter cord until it starts. When it starts it wii be at full R.P.Ms. Let run for twenty to thirty seconds. then move switch to run. Hope his helps, Thanks

Remove the plug and then plug into plug wire. With the spark plug laying on top of engine pull the recoil a couple times and you should see spark at the plug. If all is good and there is the proper mixture of gas/oil ratio in saw then >>With trigger depressed fully and choke on, pull until it fires and then shove the choke in. /////If no spark and the saw is new, I would return to retailer.

Place the saw on full choke with the switch on. Pull the rope until it fires. Place the saw on half choke, and pull again, and it will start running. Half choke should release as soon as you hit the trigger.

You may need a carb rebuild kit. they are thin rubber diaphrams and will harden up and warp if not used regularly or if the fuel is improperly mixed.
These are easy to flood if you pull them too many times on choke. Pull it on HALF choke until it pops. then turn the choke off, into the run (I) position and pull it until it starts.
If it's flooded, remove teh plug under the cover, blow off the sparking end and pull the engine a few times without the plug. this will empy the cylinder. WATCH YOUR EYES!

SOUNDS LIKE THROTTLE NEEDLE STUCK OPEN CHECK THROTTLE LINKAGE STICKING OR RETURN SPRING