Gas mixing screw will not ajust, will only run on full choke

it's sound like it need ajustement on carburator because choke only make the mixture air/gas more rich.
Or if it's very cold outside sometimes you have to wait long before out it in normal position. That do to the density of air ... if the adjusment have been made in 25C in summer and now is -15c outside the air is more dense so the motor need a mix more rich.

Many times with a gas mix, after sitting for a while, the mix separates and gums up the carb. Taking the carb off and soaking it overnight in a parts or carb cleaner and running carb cleaner through the tank and gas lines will cure this.

This is a tell tale sign of a lean fuel mixture. By choking the unit you are manually creating a richer fuel mixture. I would purchase a compression tester from a local parts store and check compression. If that's ok, I'm willing to bet the problem is still carb related. Two stroke carbs are tricky to clean because of high/low ports that are one way and sometimes impossible to clean. Did you remove high and low needles when cleaning carb? Another trick is to mix seafoam with your gas, then mix two cycle oil to proper ratio. Use 2 ounces seafoam to one gallon of gas, then mix two cycle oil to proper mix. Hope this helps! Good luck and happy wrenching!

I’m happy to assist further over the phone at https://www.6ya.com/expert/layne_0fccff498c319c32

Hi mate reverse the needle clip position back to factory setting this issue is pilot circuit for sure - If you have cleaned carbi you need to replace or clean the pilot jet and compress air clean the hole where the pilot jet came out of to clear the circuit. Running only with choke on is classic symptom of block pilot circuit...
Also check you fuel air mix screw this may have been altered trying to correct this issue it should be 1.5 - 2.5 turns out from fully closed..
all the change of needle position clip is doing is allowing your bike to run off the main jet (not good)
and reason for running with choke on is it is changes air fuel mix with choke on compensating for lack of fuel from the pilot jet blockage
regards Jamie

I would check the choke to see if it is close if not try ajusting it by losening the three screws on the right side of carb (passenger side car not running) hold acelerator left side open slitely turn black part of choke to the left till choke just closes release acelerato tighten the three scews if all that is ok check to see if by pressing acelerator with choke open if you see gas squirting (car not running)

There seems to be a blockage in the fuel supply. You will need to strip the carb and clean it, make sure that all the jets and the needle and seat are clean and the needle moves freely. Blow out all the ports and passages, be careful, there are some very small parts in a carb that can easily be lost. Also check the diaphragms for cracking and perishing. It might just pay you to install a new carb kit while you are about it.

Are you laying off the choke at any point? Full choke should only be used when starting a cold engine, it should run with no choke on full throttle. If there is not enough throttle i'd first try adjusting the tiny black screw on the carb beneath your air filter while you have it idling, letting the throttle have a little bit more room. If this doesn't work and you're running it properly than you may need to make some adjustments to the H L settings for your gas/air mix. This is also done while idling mind you and only with a clean air filter.

ok heres what you do to get your snow blower to keep running.
while you have it choked, and you get it to the running point, turn the cup bowl ajustment in/out a fraction at a time while you move the chock off slowly till you get the right setting to keep it running then ajust the setting once more to clear it up to purrr like a kitten again the vibration moves the screw out to set everything out of wack......

Clean air filter, fresh fuel mix, and saw at operating temperature before adjusting anything. HTH
Lou

double check your carb as it should have a screw for the fuel mixture. some carbs have a plastic piece over them that only lets you move the screws so far if you need more extreme adjustment they pull out about a 1/8th of a inch then you can turn in then push it back in, same principals as making a flame on a bic lighter bigger, if you cant find it take some pics of your carb and email them to me @ [email protected] and i will point them out