- 1). The first thing to check in a non start situation is your fuel. Most fuels today will lose their potency within 30 days time. Adding fuel stabilizers will help in this area. If your fuel smells remotely sour or differently from fresh fuel, it is best to change it. Keep in mind that most string trimmers take a fuel/oil mixture. Check with your owner's manual for mixture ratios.
- 2
Knowing that your fuel is good, remove the spark plug and make sure the plug is a cocoa brown color. If it is black and corroded, you should replace it. To check your spark, redneck style, plug it in to the plug wire and let it rest against the cylinder so that the bottom of the plug is contacting metal. Make sure your kill switch (if provided) is on, and gently pull the starting rope. You should be able to see spark between the electrode and ground rod. Re-install your spark plug and attempt starting. - 3
If your unit will start, but will not rev up, read on. Most 2 cycle engines will not burn all of the oil in the fuel. This excess usually ends up carbonizing on you spark arrestor screen in the muffler. Look at your muffler, if it is cool, to see if there is a removable screen on it. There are many variations depending on what brand your trimmer is. If the screen is removable, take it out and wire brush it clean, or use a pair of pliers to hold the screen and a torch to carefully burn off the carbon. Re-install the cleaned screen and attempt starting. - 4). If the above steps do not solve your problems, you may need a carburetor adjustment or re-build. This is generally not too expensive to have done and should be done by an experienced mechanic.
