Choosing a Trimmer
A string trimmer will help you give your yard a well-groomed look around trees, fence posts and other landscape objects. Choose a quality trimmer that is comfortable to carry and use.
- The Engine
Purchase a string trimmer with a quality engine, designed for the job you expect it do. The Briggs & Stratton Fource™ 4-cycle engine can be found on several brands of string trimmers. Your Briggs & Stratton dealer can help you select a trimmer that is both comfortable to use and will get the job done. Find a Briggs Stratton dealer in your area. - 2-Cycle vs. 4-Cycle Engine
You will need to choose between a string trimmer with a 2-cycle or 4-cycle engine. The 2-cycle engine runs on a mixture of gasoline and oil. This means you will have to mix the appropriate ratio of gasoline and oil and keep it on hand in a separate fuel container for your trimmer. The 4-cycle engine requires only gasoline, just like a typical lawn mower. The 4-cycle engine tends to be more powerful at lower speeds and runs cleaner, producing fewer emissions than a 2-cycle engine without a catalytic converter. 
Straight or Curved Shaft
String trimmers can have either a straight or curved shaft which connects the engine to the trimming head. The curved shaft trimmers are generally economical to purchase and work well for average-size yards. The curved shaft string trimmers are among the lightest in weight, and are easy to level for a clean cut without scalping the lawn.
Straight shaft trimmers are the choice of most landscape professionals. They provide additional reach beneath bushes and into other hard-to-reach areas. Straight-shaft models produce less vibration, which can add to their comfort level when undertaking trimming jobs that will take more than a few minutes. They often have optional attachments you can purchase for edging, hedge trimming and other trimming jobs. Somewhat heavier than curved-shaft models, straight shaft string trimmers also are more expensive.- Comfort Level
A gas-powered string trimmer generally weighs between 10 and 15 pounds, with the curved shaft trimmers being lighter than the straight-shaft models. When shopping for a string trimmer, be sure to hold the trimmer as though you were trimming, and walk with it. Does it feel balanced? Is it light-weight enough for you to handle? Most string trimmers come with a shoulder strap to help relieve pressure on your arms when carrying the trimmer. - String Trimmer Features
Some string trimmers have an automatic string-advance system, which continues to feed out the nylon cutting string as needed (the string basically wears away little by little as you trim). Other string trimmers have a bump-feed string system - you must tap the head the trimmer on the ground to advance the string. Placing new string on a trimmer the first time can be challenging. Some trimmers are easier to string than others Ð ask your dealer to explain the system on the trimmers you are interested in. Some trimmer models accept easy-to-load, individual nylon strings that you simply insert in the trimmer head. This system works well for individuals who change the line frequently.