[DannL]

Whew . . . and I thought I was the only one hearing these sounds. Here's what I surmise is happening . . . once the cooling fan is off the heat from the manifold migrates to the carburetor. The gas heats and expands making the noise. After while put your finger in the carburetor intake, you may find it wet with gas. Both my Zenith 2 and the Tillitson it replaced did this.