Recently, trimmer manufacturers have begun to produce trimmers that use four-cycle engines like those in your lawn mowers and snow blowers. Two-cycle engines have been around since the earliest days of trimming and small engines. The advantages of these operating systems will depend upon your power and trimming needs.
Power to Weight
Most four-cycle engines will generate more power than a two-cycle, simply because they have two pistons as opposed to only one. This added power will help cut the thickest, heaviest weeds, but most average trimmer users will find that a two-cycle engine has more than enough power to meet most trimming needs. Since four-cycles generate more power, they are also larger; with the extra size comes added weight, up to four pounds more than most two-cycle engines. And if you’re using the trimmer all day, this extra weight will really start adding up.
The two-cycle engines have no oil pump to distribute oil to the crankcase and piston. So, you need to use a mixed fuel to lubricate the engine. Four-cycles do away with messy mixes as they’ll run on the same gas as your lawn mower or snow blower. The two-cycle engines also don’t burn as cleanly as the four-cycles, as most four-cycles use a catalytic converter. But you’ll need to manually lubricate the crankcase on a regular basis with the four-cycles to keep them running properly. This can be troublesome and cost more money.
Four-cycles, because they have more power, more parts and a competitive advantage over the two-cycles, will cost more to purchase than most two-cycle engines. Repair costs for these engines will also run higher, because there are more parts that can break down. Two-cycles do require that mixed fuel, which can add to the cost of a two-cycle trimmer.
Basic maintenance will vary little from two-cycle to four-cycle. But repairs will cost more and be more difficult on a four-cycle engine. Two-cycles were designed to keep parts at a minimum, and accessible with only a few simple tools, which any determined homeowner can find and use. While the four-cycles operate on the same principles, repairs will be slightly more complicated, so they may require a professional.