The Stovebolt Site Forums The Shop Area Engine Shop Sticking on Idle

Check for the throttle lever to be loose on the shaft. This is pretty common on these. I weld it up with bronze welding rod. You need to remove the base from rest of the carb though. Remove the rod from the linkage at the carb lver & make sure it pulls down further. Sometimes it runs out of travel before the throttle is completely closed due to wear in the linkage.
There is an auxilary spring for this. It was a quick fix we used to sell many years ago. It is still available. Most parts stores have a card with universal throttle springs. These still come on it. It is a small spring with the loop on one end at a 90 degree angle. It hooks over the trottle speed adjustment screw & the air horn screw above it. It installs in seconds & can solve problems like this.