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Basic Weed Eater Troubleshooting Guide

Just like every other machine, weed eaters sometimes encounter problems and malfunctions. Some of these problems may require expert attention, but there are many which you can rectify by yourself.

String trimmers, another name for weed eaters, are available in three main types: gas, electric and battery powered. Although they have separate sources of power, each of these types of weed eaters operate in a similar manner to cut weeds and grass. 

All of them come with a drive shaft which holds the string. This string is being spun at a high speed by the motor of the system. When the string is spinning quickly enough, it trims any grass that it comes in contact with. 

If you are a do-it-yourself type of person, you will be able to troubleshoot and rectify some common problems that your weed eater may have as a result of usage. Here are some common problems and how to trouble shoot them depending on the type of weed eater you are using: 

  • Starting problem/difficulty starting
The man starts a weed trimmer on a lawn

Starting a gasoline powered weed trimmer motor

Starting problem or difficulty starting is mostly experienced in gasoline powered weed eaters.

  • One common cause of failure to start is a problem with fuel. If you add too much oil to the fuel in 2 cycle string trimmer, the spark plug can be affected and might cause the motor not to start. If you add too little oil to the gas, there is the tendency for the motor to get burnt. This same thing is applicable to a 4-cycle engine if the oil level drops down too low. It is advisable that you use fresh oil to the ratio of 40 parts gasoline to 1 part oil.
  • Weak or bad spark plugs can prevent the motor from starting as well. When the spark plug is bad, the motor might also run too quickly and cut out or else it might run too slowly. This means that the weed eater's engine might start but it does not function as well as it should. In this case, you have to change the spark plug in order to correct the problem. If the spark plug is good or you just changed it and you are still experiencing inconsistent running of the engine, you may need to adjust the idle speed of your weed eater.
  •  Check the screws by the side of the motor and adjust as necessary. One screw is for high speed operation while the other is for idle. You need to turn the idler set screw during idle for the motor to smoothly and effortlessly idle at the proper speed to prevent the turning of the trimmer’s head. You turn the high-speed set screw when you pull the trigger to operate the tool at a high speed. In this way, you will gain the highest rpm and the motor will still be functioning.
  • Troubleshooting for Electric and Battery Powered Weed Eaters
electric string trimmer

Electric and battery powered weed trimmers come with fewer moving parts and do not require much maintenance. However, they can also malfunction on occasion. When they sprout a problem, you can troubleshoot by yourself depending on the nature of the problem.

  • Make sure that your battery is fully charged before you start trimming so that you will be able to complete the task without running out of power. But, if your yard or lawn takes more time to be trimmed, you should consider getting a second battery or a bigger capacity battery.
  • If you are using an electric powered weed eater, make sure that the electric outlet where it will be plugged in is sturdy and able to provide the necessary power without tripping the breaker. Check along the cord for an visible wear and tear or damage. 
  • Whether the head of your trimmer is bump feed or automatic feed, it is important you use the right thickness of line and that it is properly wound. If the line is thicker, it may not feed at all and if it is thinner, it will feed too much. Check the user manual for the specified line thickness and then stick to that.
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