How do you ajust the idle speed on a sthil petrol chainsaw model 2-50

Adjust the carb using the two tuning screws marked H & L. The other one adjusts the idle speed 'tick over'

if there were one it would be on the throttle body also you can read the data sticker in the engine compartment and it will tell you if there is adjustments

The adjuster screws on a chainsaw carb are fuel screws,not air screws, so by unscrewing them anti clockwise will richen the mixture, there are normally three screws, an engine idle screw, this will operate against the throttle spindle, a screw marked L, this will adjust the fuel mixture from idle to half throttle including acceleration, and a screw marked H, this will ajust the fuel mixture from half throttle to full revs, as this will increase the maximum revs it is very importent not to exceed the manufacturers no load speeds, so a engine tacometer should be used to check this, over speeding can seriously damage the engine.

Hi
Before you remove or try to adjust your low and high speed jets you should always count the number of turns it takes to lightly seat the idle mixture screw and high speed needle adjusting screws.
Be sure to write the number of turns down on a piece of paper so you will know how many turns from the seated position to open the jets when you go to reinstall them, or if you remove them for cleaning or replacement.
If you have aready tried to adjust them then the adjustments below should get it running for you for final adjustment when warm.
Normally you will adjust your idle jet to 1/2-3/4 turn open from the bottom seated position.
Then you will re-adjust the low speed of the engine when the engine is warm by turning the idle screw in or out till the engine runs smoothly at idle speed, around 1200 RPM.
The high speed jet is adjusted to 1 1/2- 1 3/4 open from the bottom seated position, after the engine is warm.
Then re-adjusted by turning the High Speed jet adjustment screw in or out till the motor runs smoothly at high speed.
Alway use the "lightly seated" method if you have not changed the screw settings.

Hi, from your question it sounds like you have an idling problem. To fix this you have to adjust the idle speed screw that is located on top of the carb. Turn that screw in (clockwise) for faster idle speed. Hope this helps. All the best and good luck.

Anti (counter) clocwise increases oil flow (I think - it's been a while).
you won't damage it if you get wrong. Make your ajustment and rev the saw to maximum, pointing the tip of the bar at a reflective surface (about 2 inches away) for about 20 seconds if you see a layer of liquid covering about half an inch wide then the oil is ok.

Try ajusting the choke three position .

turn the high speed and low speed mixture screws right in[gently]then out 2.5 turns.start it up,screw the idle screw up till it will idle,then adjust low speed mixture screw in or out so you get the highest idle.keep lowering the idle so as you adjust the screw,it wont get it any higher in revs.so by now it should idle.next,open the throttle wide,and adjust the high speed screw until you get maximum revs..then,turn screw 1/4 turn out.that makes it slightly richer,cooling the plug with droplets of petrol.you dont want it lean.if it wont rev fully,check the fuel filter.they get dirty quite often

you need to remove cylinder barrel and check rings etc,there might be damaged to it.Usually happens if you miss oil addition to petrol.

Good Day
Vale clearance cold
intake .006 in (.15 mm)
exhaust .010 in (.25 mm)

Timing
1. With transmission in Neutral or park, start engine and warm to normal operating temp. turn eng,and all accessories off. connect Tachometer. Connect timing light to no 1 spark plug wire.

2. Disconnect and plug fuel vapor canister purge hose and EGR vacuum hose. Start and ensure idle is 900 RPM. adjust idle as required. Check ignition timing ( 12 @ 900)

3. If adjustment is required, loosen distributor hold down bolt and turn until timing is within specification. Tighten distributor hold down bolt and recheck timing. adjust idle speed as required.

hope this helps

Cheers