It is a moderately useful Android app that you are welcome to download from here. The app does some very simple math – given the size of an engine, the maximum RPM of the engine, and the volumetric efficiency of the engine, it tells you what CFM value you need when shopping for a carburetor. CFM stands for Cubic Feet per Minute.
I think I mentioned something about being frustrated with the developer tools last week, can’t remember. Anyway, it’s fine now.