The current Zenoah G26 carb is a 1/2" venturi and works great with the Mac 32. The Walbro's have a 32 in the outside of the venturi. Buy it from RCIGN1 or some place where it doesn't cost $65-$70
$65 to $75! Man that's robbery! Walbro usually lists a MSRP on their site. I'm kind of lucky as I have a couple of commercial mower sales/repair places near me. They "ONLY" charge list price!