MATCHING COILS
When coil boxes are so built that the units may be removed conveniently, as is usually the case, it often happens that the running of an engine may be improved by matching the coils and cylinders. A difference in the compression in one cylinder will often cause it to run better on one coil than on another, for no two coils will give identical results. Taking each cylinder in turn, and transposing the coil units in the box, the effect of each coil may be noted, and a combination found that will improve the operation of the engine.