Why your outdoor power equipment won't start

Anyone who uses handheld outdoor power equipment such as gasoline-powered string trimmers, leaf blowers, and chain saws has probably known the frustration of trying to start a balky machine. Most small outdoor gear come with a two-stroke engine, the type you fuel with a mixture of oil and gas. As a rule they're harder to start than four-stroke engines more commonly seen in larger equipment. Fortunately, there's a trick that often works.

All gas-powered handheld tools have a choke that lets you adjust how rich or lean the mixture of gasoline and air that goes to the engine, and for a cold start it needs to be in a closed position. A select few models have a choke that automatically adjusts, making for easier starting presuming your gear has been well maintained. But the majority of chokes are manually set, often with icons that indicate the fully open or fully closed positions.

Whenever you're starting a gas unit with a two-stroke engine and a manual choke, the usual process is to close the choke fully at first and then, once the unit has started up, to open the choke so that the engine doesn't get too rich a mixture of gas and air and flood, stalling the unit. This method, however, often results in a partial start or one in which the unit initially roars to life but suddenly—before you can close the choke—stalls out. If that happens, you could have trouble starting with the choke open or closed.

So here's the trick: Close the choke fully at first but then, once it almost or briefly starts, switch to a half-choke position until it fullly starts and can idle on its own. Also switch to half-choke if you've tried multiple cord pulls to no avail. And remember to press the throttle switch if the engine has flooded from too many pulls with the choke closed. Some products, such as the $180 Stihl MS 180 C-BE chain saw, have an actual position for the half-open stop indicating that the resulting mixture is just right. Other gear such as the Stihl BG 55 leaf blower, $150, have no formal setting yet will stay in a half-open position until you close the choke.

While testing some chain saws with especially large engines, we found them harder to start since they were more prone to flooding in warm weather. Part of the problem was that we needed a third hand to get it started. One hand was used to hold down the saw from above, using the upper handle. Another pulled the cord. But we needed a third to press the throttle switch—to allow sufficient airflow to clear the excess gas. Your foot could help to push the throttle open, but it's an awkward procedure either way.

We've updated our Ratings of new chain saws with new models, including easy-starting electrics, but check our buying guide first if you've never shopped for one or haven't in some time. Also review our Ratings of string trimmers and leaf blowers.

—Ed Perratore (@EdPerratore on Twitter)