7.5. Control of spark plugs

Visual control of a working part of spark plugs can show a condition of the engine.

If the nasal part of the isolation center is covered with a black raid, then it means that mix too rich. If the raid black and oily, then it testifies to wear of the engine and need of its check and repair. If the nasal part of the isolation center is covered with a light brown raid, then the composition of mix is optimum and the engine is in good shape.

If the nasal part of the isolation center of spark plugs pure and white, without raid, then it testifies to too poor mix. It also specifies that a candle too hot, that is heat from the central electrode is taken away slowly. If this is so, then it is necessary to adjust composition of fuel mix or to replace a candle.