We just went thorugh this in a posting labelled as clogged snowblower carb. Below are the manual and rebuild kit numbers. Pick a dealer off the Internet to buy the stuff and have at it. I didn't want to tear the whole carb apart if I didn't have to, so, I replaced the idle nut/screw assembly and it started better, but didn't run quite right. I screwed in that idle mixture screw a touch until it ran better. In retrospect, when I put in the nut/screw assembly, I noticed the new one was screwed in further than my original one. I adjusted it to match the old one, but later had to readjust it. So, it was probably set right just the way it came.
Repair kit#: 632347