Lawn mower troubleshooting basics - When gas goes bad

Lawn mower troubleshooting may very well start with the gasoline. Gasoline is a wonderful fuel. Available at your local gas station, easy to store, loaded with power producing petrochemicals, it is truly a marvel. A fact many people are unaware of is how high maintenance gasoline really is. Most of us are accustomed to filling up our gas tanks in the car, and using this gasoline over the course of several days, then refilling the tank again. The gasoline never has a chance to sit around.

Contrast this with your lawn mower, lawn tractor, leaf blower or string trimmer. You have a small gas can in the garage or shed that is filled once every two months or so. Since you are not a professional lawn maintenance person, the engine probably runs less than an hour per week. The gasoline has a chance to sit around and get bored. It may even become stale. This, my friends, is a recipe for trouble!

Gasoline does not age gracefully. In fact, it does not age well at all. After a few short weeks, it is past its prime. After several months it may degrade to the point it refuses to ignite in the engine for the power stroke. Let it sit a year, and it degrades further, eventually turning into a varnish. After several years, it reverts to a black, tar-like substance which resembles chocolate syrup ( It tastes worse than chocolate syrup, too!). In this state, the fuel is less flammable than road tar. Good luck cleaning this gunk out of your fuel system!

This process is accelerated if oil is mixed with the gasoline. Mixing oil with the gasoline is required for a two stoke engine to operate correctly. Oil / gas mixtures have a notoriously short shelf life. Manufacturers recommend mixing only as much gas and oil as can be used in about one month’s time.

With lawn mower troubleshooting, these warnings also apply to the gasoline that is in the fuel tank of the engine. If a long term storage is anticipated in a dry climate ( greater than two months time) it would be best to drain the gasoline and start the engine until all the fuel is used up.

In humid climates, another peril exists: water condensation. If the fuel tank is stored empty, water can collect, causing damage to the fuel tank and the carburetor. In these circumstances, an empty fuel tank can mean trouble, and is yet another consideration for lawn mower troubleshooting.

The solution? Gas stabilizers! These nifty additives do just what the name implies - they stabilize the fuel in a chemical sense, and prevent the rapid aging and degradation that would otherwise occur. Think of gas stabilizers as powerful antioxidants for your fuel. Fortunately, these are inexpensive, readily available at many stores, and work well with both plain gasoline and gasoline / oil mixtures. Mixing gas stabilizers with your fuel may extend the shelf life of gasoline and gas / oil mixtures for many months. Most engine manufactures endorse their use.

This does not just apply to lawn mower troubleshooting. A brief word to the wise. If you own a gasoline generator that is expected to lie dormant for months at a time, and then spring into action at a moment’s notice to supply emergency power to your home, invest in some gas stabilizer and use as directed on the package.

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