There are a wide variety of problems and resulting symptoms that can occur on a Homelite Bandit Sx-135 weed trimmer. While there may be a wide array of problems, it is important to remember that most of these will fall into one of the trimmer’s three critical operating components: spark, fuel and compression. When you need to fix your Homelite trimmer, it is important to diagnose the problem area, then test the entire system for the part or parts that are causing your problem.
Diagnose the Problem
Try starting the trimmer. Does it start but run poorly or die soon after? This can be compression or fuel related. If it doesn’t start, you may have an ignition or fuel problem. Does the trimmer start and run fine until you refuel? This problem is usually associated with the fuel system.
Perform all of the user manual's suggested self-maintenance. Clean the air filter and spark arrestor screen. Replace the spark plug. Fill the trimmer with freshly mixed gas. Make sure the ignition switch is turned on.
Try starting the trimmer again. If the problem continues, work through the following sections to isolate your problem.
Spark Related Problems
Perform a spark plug test if the trimmer won’t start. Unscrew the spark plug with the socket wrench and remove it from the engine. If the spark plug isn’t new, replace it.
Insert the new spark plug into the rubber plug it uses to connect to the ignition module. Hold the rubber plug, with the spark plug’s metal tip close to a metal point on the engine block. Try pulling on the starter cord a couple of times. Look for a blue spark across the metal points. If there’s a spark, your starting problems are fuel or compression related.
Unscrew the ignition switch’s cover on the shaft of the trimmer, if there's no spark during the spark plug test. Disconnect the ground wire to the ignition switch.
Repeat the same spark plug test. If there’s a spark with the ground wire disconnected, you have a defective ignition switch. If there’s still no spark after the second spark plug test, check the ignition’s two lead wires for corrosion, rust and loose or broken connections.
Unscrew the shaft from the engine housing and pull it off the engine. Disconnect the throttle cable from the carburetor. Unscrew the starter cover/clutch cover. Inspect the flywheel, behind the starter’s pulley mechanism, for any damage. Replace if necessary. Take the engine to a mechanic to test the ignition module for a proper circuit.
Compression Related Problems
Clean your air filter and spark arrestor screen (inside the muffler) if you haven’t already. If these are dirty they can lead to a major drop in airflow (compression) in the carburetor and piston. Check the exhaust port inside the muffler for any carbon clogs or blockages. Clean or replace the muffler if it’s damaged or too dirty to clean.
Unscrew the engine housing from the trimmer shaft if you haven’t already. Unscrew the starter cover and remove the pulley assembly from the starter cover. Inspect the pulley, starter rope and recoil spring for any damage. Make sure the starter rope pulls out and recoils properly. Replace these parts if they’re damaged.
Insert the compression gauge tool into the spark plug’s vacant hole. Pump the pressure up to 7.2 psi. There can be a small drop in pressure, but ideally there shouldn’t be any. If there’s a drop, you have an air leak somewhere in your cylinder, piston ring, piston shaft or around your crankcase.
Take the engine to a mechanic to separate and test these parts individually for the compression-related problem. Replace all of the seals and gaskets around the crankshaft and piston.
Gas Related Problems
Wash the fuel tank with a tiny amount of soapy water. Rinse it out and scrub it clean with the brush and rag. Clean the fuel tank’s cap with the brush and water. Replace the cap if it doesn’t hold a proper seal with the tank (leaks fuel) or doesn’t let exhaust escape from its check valve.
Unhook the main fuel line and the return fuel line from the carburetor. Grab and pull the fuel filter out with the metal hook through the gas filler hole. Pull out the fuel lines from the bottom of the tank. Replace both of the tank’s fuel lines and the fuel filter.
Fill the gas tank with freshly mixed gas. Set the choke to the half-open position. Start the trimmer and if it starts, immediately spray a two second blast of carburetor cleaner into the open neck of the carburetor. If the engine dies after spraying the cleaner, you will need to service your carburetor.
Let the carburetor cleaner work inside the carburetor by letting the trimmer idle for a few minutes. Depress the throttle and wait until the white smoke clears before using the trimmer. Your carburetor is dirty, and while carburetor cleaner will help, this is only a temporary solution before you need to clean or replace your carburetor.