The Complete Guide to Basic Trimmer Maintenance
How to prepare your equipment for a busy season of use

String trimmer, weed whacker, whipper snipper, line trimmer. Whatever you call this piece of equipment, it’s important to keep it well maintained throughout its useful life. In this article, we’ll discuss how to prepare your trimmer for the upcoming season, including the key areas you’ll need to inspect. We'll also share with you some maintenance tips so that your equipment continues to run efficiently. Feel free to follow along with the video as we go over each component of your trimmer and the steps involved to ensure it’s in top condition.

Drain the Fuel Tank

Before beginning any inspection or maintenance on our trimmer, the very first thing we’re going to do is drain the fuel tank of any fuel that may be left in from last season. You want to pour this into a clean container so that you can inspect that fuel for any signs of dirt or debris. Then you’ll want to flush the fuel tank out a few times until it’s clean. Now that we have drained the fuel tank we can easily move the trimmer around without any spillage. Once that is done we can start our maintenance.

Complete Guide to Basic Trimmer Maintenance: Empty the Fuel Tank

Inspect the Air Filters

Our next step is going to be to inspect the air filter. To do this we’ll need to remove the cover to expose it. If the air filter is dirty and made of felt, you simply need to wash the felt filter in warm and soapy water. Once it’s dry the air filter can go back into the machine. If you have a foam filter, it will need to be oiled before going back into the trimmer. The easiest and least messy way to do this is to place the filter in a plastic bag, add clean motor oil, and massage the oil throughout the filter. Squeeze out any excess before replacing it in your trimmer. If your filter is damaged, it should be replaced with a new one.

Complete Guide to Basic Trimmer Maintenance: Check the Air Filter

Check the Carburetor

The next step is to carefully inspect the carburetor. To do so we’re going to remove the cover, which is held in place with a couple of nuts. One of the first things we’ll check is the primer or the purge bulb. Look for any signs of cracking or aging, if you see those you’ll need to replace this part. To do so, simply remove the two screws holding it in place, then replace the bulb. You then want to check the operation of the choke to make sure it stops in the indents. We'll also look at the throttle cable and make sure there are no signs of fraying or damage, and to check that it returns to the idle position easily and is not sticking. If you had noticed any dirt or debris when you emptied the fuel tank, it would be a good idea to give the carburetor a shot of cleaner through the opening by the chokes. We'll want to clean up this area of any excess dirt and debris and allow it to dry. The next step will be to inspect the starter cord. Simply pull it out of the recoil starter and look for any signs of fraying or damage. If there is, you’ll need to remove the housing and replace the cord.

Complete Guide to Basic Trimmer Maintenance: Check the Carburetor

Muffler and Spark Plug

Once we’re done with the carburetor, we’ll next look at the muffler or spark arrester. To inspect this we first need to remove the protective guard. Once we do that we can now look at the muffler, making careful note of any signs of corrosion or rust which may impair the performance of the muffler. Then we’ll remove the cover to check the spark arrestor as well. You want to make sure that there is no damage to the screen, and if so you’ll need to replace it. Once that’s done, replace the screen and put the cover and guard back on. The last part to check with the engine is the spark plug. Using a proper size plug wrench, we’ll remove the spark plug and check for any signs of corrosion or wear on the actual tip. If you see that kind of damage you should discard the plug. If you can, the plug can be carefully cleaned with a wire brush. We recommend that you put a fresh plug into your trimmer at the start of the season, and continue to check on it throughout the year. If replacing the plug, make sure the gap is set to the manufacturer's specifications.

Complete Guide to Basic Trimmer Maintenance: Inspect the Spark Plug

Trimmer Head

Now that we’re done inspecting the engine components, we’re next going to look at the trimmer head. First, we will check the trimmer guard for any signs of cracks or damage. You’ll want to replace the guard if it is showing any of those signs. Then check the blade for the line cutter and make sure it’s in good shape. If not, you can simply replace that individually once we’ve inspected all of the trimmer. Next, we’ll look at the trimmer head itself. If it is damaged, you should replace the complete unit. Then we’ll verify that it is working properly. If it has a “tap and go” kind of system where you bump to release the line, make sure that is working.

Complete Guide to Basic Trimmer Maintenance: Check the Trimmer Head

Install New Line

Now is a good time to install some new line in your trimmer head so it’s ready when the season starts. First remove the cover and the spool from the holder, again checking for any signs of damage. If there is, you may simply want to replace the whole head with a new one. Then we’ll remove any remaining line and discard it. Then, following the manufacturer's instructions, we’ll cut the pre-determined length of the appropriately sized line and install it on the spool. Make sure you do not put any more line on the spool than is recommended. Then reinstall the spool onto the holder, and ensure that you have roughly equal amounts of line hanging out on both ends. Now you’re ready to put that assembly back on the trimmer head by carefully lining up the tabs on the base with the openings on the head itself and once again check that the bottom button moves freely.

Complete Guide to Basic Trimmer Maintenance: Install New Line

Tighten 'er Up

Now that we’ve got the trimmer head reassembled, we want to make sure that it is tight to the shaft. So we’re going to flip the unit back over and secure it. Most trimmers will have a mechanism for locking the gear so they don’t turn as you’re tightening the head. It typically involves either a pin or a small blade. A screwdriver will fit down through the opening to lock the assembly. Determine whether your trimmer is a left hand or right-hand thread, and turn the thread in the appropriate direction.

Complete Guide to Basic Trimmer Maintenance: Tighten the Trimmer Head

Let 'er Rip!

Now that we’ve completed our inspection and maintenance, we’re going to add a bit of fuel to make sure it runs properly. Once that’s complete, we’ll drain that fuel and wait for the season to start. Remember to check on the condition of items like the air filter, spark plugs, and head guard throughout the season for signs of damage. If you’ve noticed your trimmer requires some new parts, we have thousands of manufacturer-approved trimmer parts, which you can find by searching for your model number. For more tips and tricks, be sure to subscribe to our YouTube channel!