I have a mtd 3.5hp 21" snow blower it was bought new in 11/06 the problem im having is stalling it starts ok some times other times it stalls and won't run others it will only run at full choke if u turn choke down even to half choke afer 15minutes of running it stalls itll start right back up after pushing the primer button 1 to 3 times but keeps stalling and wont stay running

check air filter and or carb cleaning --rebuild or replacement

sounds lie the Carburetor needle valve is restricted so you are basically running out of gas. By the time you move around to start it again, a little gas filled the Carb Bowl again. Take the Bowl off the carb and if the Needle valve is all metal, check up where the needle valve goes to see if the Seat up there is cracked from being dried out by ethanol fuel. If the Seat is the rubber ind, it can be replaced for cheap.

It,s already set to specs when u buy it u need to call The service center or store where was bought...being new u should not do anything to some thing new and still under warranty

clean the carb
put fresh gas in it
change the spark plug

sounds like carb needs cleaning or plug changed
id do both

you need to thin out your mixture on the carb. should solve this.

Single-Stage Gas Snow Blower Parts

Single Stage Snow Throwers by MTD Products

Yard Machines Snowblower Parts

Yard Machines Snowblower Parts

What engine do you have? Tecumseh those are usual 18-21oz Not sure with briggs, but will be around a 1/2 qt (16oz) start there. Add a little at a time to bring level up. get back if you have and need more specifics.

Hi, Check for weak spark. You may need to replace magnedo or clean it up abit. Another thing clean out carbereter jets this could be the main reason why it stalls.