Someone was asking about a/f ratios a few weeks ago.
From Clarence Lee's column, RCM, January 2004, p. 42:
"The Walbro carburetors are intended for gasoline operation and gasoline burns at a lean air/fuel ratio of 14.7:1 and rich at about 12.5:1. Methanol, on the other hand, burns at a lean air/fuel ratio of 6.45:1 and rich at about 4:1. As such, a Walbro carburetor intended for gasoline usage will not pass sufficient fuel if used with methanol."
I know that the question asked was only about methanol, but it seems best to give the quotation as it stands in RCM rather than paraphrasing it.
Marty