Causes for a Ryobi Gas Trimmer That Will Not Start

If your Ryobi string trimmer won't start, it's possible you're not using the proper starting procedure. Both two-cycle and four-cycle models come with specific starting instructions. If you're using the proper procedure, though, hard starting becomes a maintenance issue. Start by cleaning the air filter and spark plug, and if you still can't get the trimmer going, the problem is probably fuel-related. You may have to drain all the fuel and replace it.

Garden Strimmer In Motion.
credit: samer chand/iStock/Getty Images
Ryobi makes a variety of string trimmer styles that make quick work of trimming grass and weeds.

Starting Instructions

Whether you own a two-cycle Ryobi trimmer which runs on a mixture of gas and oil, or you own a four-cycle model to which you add oil separately, the starting procedure is the same. • Start by pushing the primer bulb from eight to 10 times. You should see fuel in the bulb after seven pushes -- if not, keep pushing until you do. • Set the choke to "Full" or "Cold Start" and pull the starter rope. • Stop after four pulls and reset the choke to "Half " or "Warm Start" before pulling again. Failure to readjust the choke usually results in flooding and a 10-minute wait before you can try again.

Routine Maintenance

Both the air filter and spark plug on your Ryobi trimmer need servicing, and both can cause starting problems. To clean the air filter, release the latch on the air filter cover, remove the filter and wash it in warm soapy water. If you can't clean it, replace it. Remove the spark plug by pulling off the boot and unscrewing the plug with a spark plug wrench. Check the spark plug electrodes -- if they are blackened with carbon deposits, that's probably a result of running the trimmer with a dirty air filter. Clean the electrodes with a file. If the electrodes are worn, replace the plug -- which you should do every year in any case.

Extended Storage

If you can't get fuel into the priming bulb, no matter how many times you press it, the trimmer has a blockage in the fuel line, and you should bring it in for servicing. If the bulb is full and the trimmer won't start, even after replacing the air filter and plug, then the fuel may be bad. If you stored your trimmer in the shed over the winter with fuel in the tank, there's a good chance that moisture has collected in the bottom of the fuel tank or in the carburetor, or varnishes have settled in the fuel lines. If so, you can do a couple of things about it.

Clearing out Old Fuel

If you forgot to change your fuel before you put your trimmer in storage, there's no time like the present to rectify the situation. • Pour all the old fuel into an approved container for disposal and replace it with fresh fuel; don't forget to add oil in a 50-to-1 proportion if you have a two-cycle model. That may be all you need to do to get the trimmer going again, but if not: • Remove the air filter and spray a 1-second squirt of starting fluid into the air intake. That should ignite the old fuel that's in the carburetor, and once the engine is running, the rest should burn off. The engine may smoke for a short period.