Have you ever wondered why gas caps on new equipment seem to be larger these days? We did, so we talked to some folks from Stihl at their recent event in Virginia Beach. The answer, as it turns out, is because these newer gas caps house charcoal. But, why charcoal gas caps?
Why Charcoal Gas Caps?
As Stihl tells us, the implementation of charcoal gas caps has to do with an EPA regulation that seeks to regulate gas fumes. Charcoal, as you may or may not know, acts as an air filter, and these new, larger gas caps can accommodate more charcoal.
The charcoal gas caps have some venting that allows air to enter through the cap and filtered as it enters the tank and pushes fuel to the carburetor. When you turn the engine off, fumes escape through the vented cap, but become trapped by the charcoal filter. When you start the engine later, those trapped fumes flush back out into the tank as air is pulled back through the cap.
The charcoal gas cap will last indefinitely, provided you don’t ever saturate it with fuel. Stihl recommends that you never store or transport a machine on its side with a full tank of fuel for this reason. Fuel will clog the cap, which will inhibit air flow and cause engine malfunctions. It will also cause charcoal dust to deposit into your fuel tank.
The more you know, right?
