Chainsaw Repair

Walbro sells a special carb for 25-30cc model airplane engines the WT-499 that can be adjusted to run Alcohol as well as gasoline.

It was made up years ago for the Zenoah G23 alcohol model airplane engine but just happens to work fine on gasoline if the needles are closed down some.

Those Zenoah alcohol engines didn't work out so well as the bearings would turn to rust on the inside.

But the WT-499 is still around. It has a 27/64" (11.11mm) venturi

http://www.davesmotors.com/walbro-wt-499-alcohol-carburetor.html