Gas String Trimmers

Four-stroke trimmers: less polluting but heavy and expensive

Gas string trimmers do a better job of trimming tough weeds than most electric trimmers, but gas-powered trimmers are louder and pollute more than electric models. Most are also heavier and require more maintenance.

Gas-powered string trimmers that use four-stroke engines are quieter and pollute up to 75 percent less than two-stroke models, and use straight gasoline instead of requiring a gas/oil mixture. They also tend to run with less vibration. On the downside, they are heavier than two-stroke models (heavy enough that you might need to wear a shoulder harness) and require regular lubrication.

After its comparison test of 12 gas string trimmers, Popular Mechanics praises the four-stroke, 25cc Honda HHT25SLTAT (*Est. $350), saying it offers "smooth, vibration-free performance." The review classifies this model as a "near-pro" trimmer. The engine can be tilted in any position without danger of damaging it. The main drawback, aside from the Honda string trimmer's high cost, is that it weighs 13 pounds without the gasoline.

The same review also singles out the professional Shindaiwa T2510 gas trimmer (*Est. $400) with a hybrid four-cycle/two-stroke engine, which minimizes emissions and weight (11 pounds dry), but still requires you to mix oil with the gasoline. Although this string trimmer is also named a ConsumerGuide.com Best Buy (the review was written in 2007), we've found quite a few recent comments in professional landscaping forums that criticize such hybrid engines for maintenance problems. Both the Honda and the Shindaiwa gasoline-powered string trimmers are available mainly at specialty stores.

Among less expensive four-stroke gas trimmers, the 29 cc Craftsman 79197 (*Est. $200) is a ConsumerGuide.com Best Buy as of 2008, and this model also gets top ratings in owner-written reviews at Sears.com, earning 4.2 out of five stars. Instead of bump feed, the Craftsman 79197 gas trimmer uses lengths of precut line. Refills require the operator to stop the engine, but they're quick, and the engine restarts easily. Its split-shaft configuration enables the use of various attachments -- a hedge trimmer, pole saw, blower and more. On the downside, the Craftsman 79197 string trimmer weighs 20 pounds, and it doesn't come with a shoulder strap. Buyers get a two-year warranty with the purchase.

The best four-stroke trimmer is Honda HHT25SLTAT, but it costs nearly $400. The Craftsman 79197 appears to be the best compromise; it costs $150 less, accepts attachments and gets high ratings from owners -- but at 20 pounds, you'll need to use a shoulder strap.

Two-stroke gas trimmers: lighter and cheaper, but not as green

Two-stroke gas trimmers are generally cheaper, but you'll need to mix gas and oil before fueling them. While more polluting, they weigh far less than four-stroke gas trimmers. Some models improve emissions by including a catalytic converter on the engine, which helps them obtain certification from the California Air Resources Board (CARB), although such trimmers may be hard to find in other states.

Echo string trimmers get high ratings for easy startups, but use 21 cc engines that aren't as powerful for tackling tough weeds as some other two-stroke engines are. Instead of the usual bump feed, some Echo trimmers use precut line refills that are inserted between two eyelets. Echo calls it the Rapid-Loader system and some owners confirm that once you get used to it, refills do take just seconds. Others complain that since you have to stop the engine to do it, it's a pain.

Popular Mechanics tests the 21 cc Echo GT-200R (*Est. $170), which weighs only 9.3 pounds and comes with a five-year warranty. Tests confirm that it's easy to start, and the editors of Popular Mechanics say it's "the only curved shaft that cuts like a pro." In owner reviews at HomeDepot.com, the Echo string trimmer gets a pretty good average score of 3.9 out of five stars. More than 20 reviews are posted on Epinions.com, with those dated 2008 or later predominantly favorable. Overall, owners posting at Epinions.com either love the Echo GT-200R string trimmer or hate it; most give it either a one star out of five or a five out of five. Complaints center around the trimmer's Rapid-Loader system and the need to replace the line too often. Some owners warn that the curved shaft is too short for anyone over 6 feet tall.

For more money, the heavier (12.4 pounds) straight-shaft 21 cc Echo SRM-225i (*Est. $250) features Echo's i-75 i-start technology, which reduces starting effort by 75 percent, according to Echo's website. This gas trimmer is more comfortable for taller people and uses a bump-feed spool head. It also carries a five-year warranty. A CARB-certified version is available in California (where emissions restrictions are more stringent).

The Stihl HomeScaper Series FS 45 (*Est. $140) has a 27 cc engine -- powerful enough for weeds and tall grass -- and weighs 10.8 pounds. It uses a standard bump feed to advance the line. A related model, the Stihl FS 45 C-E Easy2Start (*Est. $175) is supposed to provide assisted starting, but tests at Popular Mechanics say the system doesn't make the Stihl trimmer particularly easy to start. The Stihl FS 45 string trimmer variants are given high ratings in one professional test, however. In California, a version is available with a catalytic muffler to meet CARB requirements.

Below about $200, even the best gas trimmers are competing head to head with the best corded electric trimmers discussed above, which cost less yet handle weeds as well or better. We found mixed reviews for most budget gas trimmers, with lots of complaints about breakdowns. If you can spend more on one of the better models discussed earlier, reviews say you're more apt to be satisfied in the long run.

The Weed Eater Featherlite SST25 (*Est. $105) is rated highly in one professional test and is named the best value among near-pro models by Popular Mechanics. It gets only three out of five stars from owners posting reviews at Amazon.com, however, with some complaining that it is hard to start and doesn't idle properly. The 25 cc Craftsman 79103 curved-shaft string trimmer gets 3.6 out of five stars from owners at Sears.com. It accepts attachments and has spring-assisted starting and most owners say they find it quite manageable at 12.5 pounds. In this price range, reviewers say a budget electric string trimmer is a better choice if you mainly need to trim grass. If you really need to cut weeds and tall grass, you need a more expensive model.