The Following Insights will Surely Spark Your Interest

In order for your small engine to run properly, timed explosions of a fuel and air mixture inside the engine's cylinder occur in rapid succession. The component responsible for igniting these explosions is called a spark plug.

Diagnosing and replacement of this component requires both specialized and basic hand tools, however if you do decide to remove a plug you suspect is faulty please consider the following:

A key takeaway from this post is if you happen to install a spark plug in your lawnmower or other small engine machine, always ensure it is the correct one! Yes, you can install incorrect spark plugs into small engines with varying results, none of which are good.

The length of the threaded portion of the spark plug is called the reach, and can vary between plug models. If you happen to install the incorrect spark plug with a greater reach into your lawn mower, because it is longer than it was intended to be it will reach down further into the cylinder; engine damage will result as the piston will rise and hit the extended portion of the plug. If an incorrect plug is installed with a shorter than necessary reach, the air and fuel mixture will burn too slowly, resulting in hard starting and a loss of power. Again, always install the correct plug stipulated by the engine manufacturer.

Routine maintenance is key for rotary lawn mowers; manufacturers generally advise servicing spark plugs like this one, approximately after 100 hours of operation.

Furthermore, spark plugs run at different heat ranges, and the correct plug will run at the optimal heat range.

If a colder plug is incorrectly installed in a colder running engine: heavy carbon deposits will form over the portion of the plug where the spark jumps a gap. (Normally, when running at ideal heat range this carbon would be burned off naturally in combustion process).

If a hotter plug is installed in a hotter running engine, the plug may overheat.

In the next post, we will present the concept of spark plug "gaps", cross-referencing compatible spark plugs, and how to read plugs that have been removed from your engine.