A sticky throttle in cold weather may be caused by corrosion on the carburetor operating arm pivot shaft. The operating arm is that portion of the carburetor to which the throttle tension spring is connected and by which the accelerator pump arm is driven. This is likely to be the cause if the problem is present when the engine is stone cold but disappears once operating temperature has been reached.
Disassembly and cleaning is simple, requiring the disconnection of the throttle linkage at the carburetor, removal of the operating retaining lock ring, and the disconnection of the throttle tension spring. Clean the pivot shaft with emery cloth and run your battery terminal wire brush through the operating arm bearing. Apply a little engine oil to the operating arm bearing and pivot, then reassemble.
Author: Walter Light