Ask The Editors: How Often Do I Replace My ATV’s Spark Plug?
How often do these things wear out?
2-strokes were very different animals. Because oil was literally mixed with the gasoline entering the combustion chamber, there were two possible outcomes to every single plug fire – liquid oil all over the plug’s electrode or said oil burning up into a flash of carbon.
Either way, plug life on a 2-stroke was short indeed.
Today we have several advantages when it comes to the life of our plugs. You named the 4-stroke engine design, which eliminates the whole gasoline/ oil lube mix altogether (thus burning much cleaner) but also things like computer-controlled fuel injection have all but eliminated the jetting woes of yesteryear that contributed to fouling plugs.
Still, it may look perfect to the naked eye, but plugs do wear out on every engine ever made. Why? Out good pal physics again. Gap erosion is the term for the loss of material on either the electrode or ground strap that is inevitable over time.
Every single time a plug fires, a bit of material goes with it (and don’t forget, your plug is literally the catalyst for an explosion that is taking place 20 times every second.
We usually follow manufacture recommendations when it comes to plug replacement intervals, as nobody knows a given engine better than they but if you aren’t sure what those are or wish to err to the side of performance caution, popping a new plug in every 100 hours of operation is a pretty safe way to insure your plug is always in good shape.
