Perhaps I owe a slightly more “professional” explanation regarding the adjustment of the mechanical ignition regulator,…
A lot has already been said about the properties of wood gas in comparison with gasoline, but I would still like to mention them:
lower burning temperature, slower flame spread.
Given these facts, it is necessary to adjust the ignition timing. If we take operation with low revs and low load, we find that the absolute pressure in the intake manifold is higher than when operating with gasoline, so this pressure must already at a higher value move the ignition timing forward to the extreme limit with the help of the “vacuum” membrane, in practice this means that we reduce the spring force against the membrane.
Slower flame spread means that the ignition timing needs to be advanced more “aggressively” in terms of increasing the revs, which again means in practice that the springs on the centrifugal governor need to be a bit more gentle, as the engine revs don’t go as high, and the engine needs more pre-ignition even at lower revs than on gasoline, which is faster.
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