PURPOSE: To make it possible to adjust the titled engine in accordance with the purpose of using the engine by a method wherein the output of a micro-computor transmitted to various machines and devices is varied properly on the base of the output signal of at least one of various sensors for detecting the operation condition of the engine.

CONSTITUTION: In case where the number of revolutions of the engine is comparatively small and the output signal of a senser 14 (such as a pressure sensor) does not coincide with data stored in a detecting section 15 in advance, the detecting section does not operate changeover switches 13 and 17 and therefore, the engine controls a power transistor 4 in response to the output signals of the sensors 14 and 16 as usual so that the expected ignition operation is attained through an ignition coil 2. On the other hand, when the output signal of the pressure sensor 14 coincides with the data stored in the detection section 15, both of the changeover switches 13 and 17 are switched to the condition shown in the drawing and the power transistor 3 is controlled by a shift register section 7 in response to a signal 8 obtained by varying the phase of an ignition signal 4 by a valve determined at a phase determining section 12.