My husqvarna 122c starts fine with the choke on. When the choke is turned off, the motor revs very high then eventually dies. If I feather the press the throttle, it dies right away? carb issues?

Hi David-
I found this youtube video regarding 122c Husqvarna throttle cable placement.
https://www.youtube.com/watch?v=eUwaRtzhaQ0

I found this link regarding your Husqvarna 122C owners manual (OM) and Parts List (IPL).
https://www.husqvarna.com/ca-en/support/manuals-downloads/

I also found this link regarding Workshop manual for your Husqvarna 122C trimmer.
https://www.google.com/search?ei=BLHeXZv8I4-WsQWBhYjoBA&q=How+is+the+throttle+cable+and+tube+routed+from+trigger+to+carburetor+122c+Husqvarna%3F&oq=How+is+the+throttle+cable+and+tube+routed+from+trigger+to+carburetor+122c+Husqvarna%3F&gs_l=psy-ab.3...9359.61712..73674...0.2..0.130.2047.3j16......0....1..gws-wiz.......0i71j33i10.d34Ms2LVkiY&ved=0ahUKEwibjtGE9IrmAhUPS6wKHYECAk0Q4dUDCAs&uact=5
Click on (pdf)Workshop Manual 265/252/250... link.

Hope this helps.

Back up your low screw 1/4 turn that should remedy your problem...

You will need a special tool to adjust the anti tamper screws, do not adjust them to over come some underlying problem i.e dirty fuel, blocked air filter or dirty or blocked air filter. if the screws have not been touched this will be a good starting point, both screws are fuel screws so unscrewing will increase and richen the mixture,
Always start with the L screw first, with the engine running gently screw the adjuster in leaning the mixture, the engine rpm will start to increase, at the point where the engine then starts to die unscrew the adjuster about 10 minutes on a clock face, the H screw will control the high rpm, with the trimmer cord pulled out to the correct length open the throttle fully, screw the adjuster slowly in or out to achieve the greatest maximum speed too far in it will die, too far out it will die, allow the engine to idle, snap the throttle open it should pick up without hesitation, if not turn the L screw our slightly to increase the fuel supply.

Turn mixture screws completely in gently, then wind out 11/2 turns each. The saw will be able to start and run at this point. On idle wind Low clockwise till motor starts to die then anti-clockwise 3/4 turn.
High speed is a little more difficult, On full revs wind clockwise till saw starts to rev out (lean Mixture) then back till the sound starts to bubble.

Needs a carb adjustment, cleaning, or possible rebuilt. Try adding a little seafoam and running at half choke for about 5 mins or longer this may clean it up nicely. also check the spark plug.

get it running on idle,adjust the idle down till it runs hairy,then adjust low speed mixture screw till you get it highest revs,then keep repeating that till you get it idling normal.rev saw up max revs,adjust high speed jet, in or out till you get max revs,then screw out one quater of a turn.That lets enough fuel thru to cool the sparkplug tip..If thats no good,redo the carbi.Check the tiny filter under the needlevalve hole.Check the needlevalve diaphragm height.recheck gaskets are right way round

the motor wont rev high on choke.the motor is suppose to fire once on choke. then turn the choke off.pull the start cord and the motor should start and run.check that the throttle conrol is on full. it should run fine.

check ur governor spring or linkage---adjust air/ fuel mixture

if he put fuel in it dump it out & put yours in it , if problem persist there are 2 screws on the carberator turn the 1 on the right or th bottom 1/4 turn to the left!

As with all 2 strokes if you have compression and a reasonable spark, you only need fresh fuel with correct oil ratio) and they must go !(as long as you haven't fiddled first and all gaskets are sealing) I start mine by(1) pumping the primer till it is firm,(2) full choke,(3) pull till it kicks ONCE,(4) half choke, pull till it runs,allow to warm up and(5) switch to run (you may need to apply a bit of throttle while pulling as in (4)(or give it a few more pumps if it dies) If all is ok, check that when properly warmed up there is a smooth transition from idle to full revs, if it hesitates it may need the LOW SPEED mixture leaning (clockwise) SLIGHTLY.If it dies the LOW SPEED mixture may need richening(anti-clockwise)(adjust 1/8 turn at a time) Make sure that motor is just peaking at full revs and is on the RICH side of peaking (HIGH SPEED mixture)(this will avoid seizing it Adjust both till it revs cleanly and is JUST rich at full, and idleing nicely and it should start without too much trouble.(If you have fiddled and are lost,-about 2 1/2 turns out from closed on both needles should get you started)