"This is a workshop we conducted to convert an electric off grid generator to run on wood gas. We made some simple modifications to the intake manifold for dual fuel operation, but the really neat thing is that we built an electronic carburetor using a simple Arduino micro-controller (radioshack) and an oxygen sensor with a servo to operate it. What this does is automate the air fuel ratio of the biofuel for a clean, strong burn.
With some simple modifications you could adapt this to other types of biogas and even alcohol fueled engines.
A powerful little piece of technology now made possible by the Maker revolution! If you can get a little help soldering and welding, then this is the project for you."