The long hours and weekend work that often arrives with summer means you may be hauling out some equipment that had been stored away for the winter, or backup machines that you only use during your busiest months. Basic maintenance will help keep your 2-cycle engines running in the field and out of sickbay.
Today's leaner-burning 2-cycle engines are designed and built for lower emission levels and are simply not as forgiving as the older, pre-EPA/CARB units. With the substantially smaller margin for error of these new engines, maintenance takes on a whole new level of importance.
Generally, a major failure in a 2-cycle engine is not caused by just one factor. More often, failure is due to a combination of problems. In the past, engines could operate with several systems in less-than-perfect condition, such as plugged cylinder fins, debris in the air intake, and partially plugged fuel filters. With the smaller operating window in today's regulated environment, it could take a problem in only one area to increase operating temperature beyond limits, leading to engine failure.
1. Cooling System
The typical 2-cycle engine is air-cooled and relies on its air passages and other cooling surfaces to be free and clear of any restrictions. Dirt, debris, and leaves have a tendency to collect in these areas, particularly if spilled fuel residue is present. It is very important that these areas are clean and free of any foreign material that can restrict air flow.
2. Fuel Filter
Inspect, clean, or replace the fuel filter every 10 to 15 hours of use. Debris in the fuel tank will necessitate more frequent filter replacement. Some commercial contractors carry a spare fuel filter assembly in their pocket just in case the fuel filter gets semi-plugged with debris and starts to affect engine performance.
3. Air Filter
A partially clogged air filter can cause an engine to run too rich. Make sure you have plenty of replacement air filters on hand, and replace them periodically.
4. Muffler & Spark Arresters
It is important to maintain the muffler and the spark arrester. A plugged muffler or spark arrester screen will dramatically change the way an engine operates and performs. Never let debris accumulate around the muffler. It may prevent proper engine cooling, and even become a fire hazard. In most areas, it is required that mufflers be equipped with a spark arrester. A muffler without a spark arrester properly installed (and clean) is a potential fire hazard.
5. Fuel & 2-Cycle Oil Mix
Use only a brand name gasoline that is fresh and clean. The lower cost, discount brand gasoline may be old and not have quality components. As true with most everything these days, you really do get what you pay for when it comes to the gasoline you buy at the pump.
Some gasolines contain an oxygenate (like alcohol) for cleaner combustion and reduced exhaust gas emissions. Oxygenated fuels such as methanol and ethanol may cause a dramatic increase in engine operating temperatures; this is especially true if simple, basic maintenance is not performed on a regular basis. Also, under certain conditions, alcohol-based fuels may also reduce the lubricating qualities of some mixing oils. Never use any fuel containing more that 10% alcohol by volume. An octane rating of 87 or higher is always preferred.
It is important to mix your fuel with a name brand 2-cycle engine oil at either 40:1 or 50:1, depending on the manufacturer's recommendation, which can be found in the owner's manual. Avoid the generic, multi-purpose oils and high-ratio oils. These mixing oils are really not suitable for today's leaner running, high-performance 2-cycle engines. Be sure to mix only enough fuel for your immediate needs. If fuel must be stored longer than 30 days, it should be first treated with a good quality fuel stabilizer.