The Best Weed Eaters: Two or Four-Cycle?

More and more manufacturers are starting to produce four-cycle engines in an area long dominated by the two-cycle, or two-stroke, engine. Four-cycles use four strokes of the piston to power the engine, drive out the exhaust, intake new fuel and provide compression. A two-cycle only uses two strokes for the same process. While each has its advantages and disadvantages, the real test comes with personal preference and your trimming necessities.

The torque on a four-cycle, with the added strokes, gives it the advantage for power. However, the more parts are required to pump and lubricate the crankcase. With more parts comes more weight, generally 2 to 5 lbs. more than a two-cycle. Two-cycles generally deliver a sufficient amount of power to finish almost any trimming job, except maybe thick brush and taller weeds. Most homeowners and professionals will not need the extra power of the four-stroke.

Since the four-stroke needs four full up-and-down rotations of the piston to get moving, starting the engine will also be more difficult. The two-cycle will get the flywheel spinning faster, as the engine only needs two strokes to complete the cycle. Once the engine starts, the vibration caused in the extra movements on the four-cycle tend to create more vibration, which can be harder on the joints. However, if more torque is need to get the job done, the added vibration won’t matter if you can get the job done in less time.

Since the four-cycle uses more parts to function, it also has more parts that can break down. Two-strokes have only a few moving parts: crankshaft and piston, which means less parts to supply the power. Two-cycles, designed with simplicity, will be much less complicated to disassemble, repair and put back together. A four-cycle may require a professional mechanic. Four-cycles also use an oil pump to lubricate the crankcase, unlike the two-cycles, which get their lubrication from the premixed fuel. This means that, after every 25 to 30 hours of operation on the four-cycle, you’ll need to change the oil.

Four-cycle engines don’t need a mixed fuel. This gives them a cleaner, quieter engine that produces less harmful emissions for the environment. This also adds to their fuel economy, which will stretch farther than the two-cycle. Two-cycle engines will require a ready source of mixed fuel. This mixed fuel will go bad after just 30 days, so if it’s not used, it’ll need to be dumped. If you use the trimmer on a regular basis, however, this will be less complicated than counting the hours until the next oil change.