Trimmer Plus String trimmer won't start: Common Causes & How to Fix
1String Trimmer Spark Plug
Most Common Solution
Repair Instructions:
Check the spark plug for any wear or damage issues. If the porcelain part is cracked, the electrodes are burned or bent, or there's heavy carbon buildup by the electrode, replace the spark plug. You can use a spark plug tester tool to check if the plug is bad. When cranking the engine, you should see a strong spark jump between the tester terminals. No spark means the plug is faulty and needs a swap out. Spark plugs need to ignite the fuel mixture. But cracks, carbon buildup, and electrode damage can prevent the plug from sparking right. Inspect closely for any of those problems. If present, put in a new plug. Testing with a spark checker will also confirm if the plug is firing properly or if replacement is required. Good sparking is a must for ignition.
How to Replace String Trimmer Spark Plug
- Make sure the Trimmer Plus string trimmer is turned off and disconnected from any power source. This ensures the trimmer won't accidentally start up while you're working on it.
- Locate the spark plug. It's usually found at the very base of the trimmer near the engine. Refer to your owner's manual if you're unsure of the location.
- Remove any covers or shrouds covering the spark plug. Many trimmers have plastic covers that need removing to access the plug.
- Clean away any dirt, grass clippings or debris from around the spark plug area. This allows you to access the plug easier. Use compressed air if available.
- Use the appropriate size spark plug socket wrench to remove the old spark plug. Turn counterclockwise to loosen and remove.
- Inspect the old spark plug. Look for damage like cracks, excessive wear or carbon buildup. This can indicate issues with the engine.
- Check the new spark plug gap using a gap tool. Adjust the gap if needed per your owner's manual specifications.
- Install the new spark plug by hand threading it clockwise into the engine cylinder head. Tighten with the socket wrench once threaded. Don't overtighten.
- Replace any shrouds or covers that were removed to access the spark plug area. Make sure they are securely reattached.
- Reconnect the spark plug wire to the new spark plug, if it was disconnected. Make sure the connection is snug.
- Start the trimmer and test for proper operation. Let the engine run for a minute to ensure proper spark.
2String Trimmer Carburetor
Most Common Solution
Repair Instructions:
The issue could be that the carburetor is clogged up. This is usually caused by leaving old gas in the Trimmer Plus string trimmer. Over time, some of the ingredients in the fuel can evaporate. This leaves a thicker, stickier substance. That sticky stuff can clog up the carburetor and stop the engine from starting. If the carburetor is choked with gunk, try cleaning it out with carburetor cleaner spray. If that doesn't work, you may need to rebuild or replace the whole carburetor. Leaving old gas sits and turns sticky. Those deposits restrict proper fuel flow through the carburetor passages. Try solvents to dissolve the clogs first. But if it's severely gummed up internally, a carburetor rebuild or replacement may be required to get it working properly again.
How to Replace String Trimmer Carburetor
- Disconnect the spark plug wire from the spark plug. This prevents accidental starting while working.
- Drain the gas from the fuel tank and carburetor. Consult your owner's manual for proper draining procedures. Catch gas in an approved container.
- Remove air filter and cover to access the carburetor. Make note of how parts are assembled.
- Detach fuel line connecting the carburetor to the gas tank. Use pliers and catch any spilled gas with a rag.
- Remove carburetor mounting nuts using appropriate sized wrench or socket. Caution - carb may contain gas so position accordingly.
- Remove old carburetor from the trimmer. Make note of linkage and choke plate connections for reassembly.
- Attach linkages and choke plate to new replacement carburetor. Consult the manual for proper configuration.
- Mount new carburetor with mounting nuts removed earlier. Do not over tighten.
- Reattach fuel line to the carburetor inlet. Confirm no leaks.
- Replace air filter and cover. Make sure all parts are assembled properly.
- Add fresh gas to fuel tank. Use manufacturer-recommended fuel.
- Reconnect spark plug wire to plug.
- Start trimmer and test for smooth operation. May require carburetor adjustment.
3String Trimmer Carburetor Repair Kit
Most Common Solution
Repair Instructions:
The issue could be that the carburetor is clogged up. This is usually caused by leaving old gas in the Trimmer Plus string trimmer. Over time, some of the ingredients in the fuel can evaporate. This leaves a thicker, stickier substance. That sticky stuff can clog up the carburetor and stop the engine from starting. If the carburetor is choked with gunk, try cleaning it out with carburetor cleaner spray. If that doesn't work, you may need to rebuild or replace the whole carburetor. Leaving old gas sits and turns sticky. Those deposits restrict proper fuel flow through the carburetor passages. Try solvents to dissolve the clogs first. But if it's severely gummed up internally, a carburetor rebuild or replacement may be required to get it working properly again.
How to Replace String Trimmer Carburetor Repair Kit
- Remove air filter cover and air filter to access the carburetor.
- Drain fuel tank and disconnect fuel line from the carburetor inlet. Catch fuel in approved container.
- Remove carburetor by taking out the mounting nuts and detaching linkages/switches. Note connections.
- Disassemble carburetor by removing bowl screws or cover, float pin, needle valve and jet.
- Clean carburetor parts with carburetor cleaner spray and a small wire brush. Inspect parts for damage.
- Install new parts from repair kit - may include float, needle valve, seals, and gaskets. Consult manual.
- Reassemble carburetor with new parts. Confirm float moves freely.
- Mount carburetor back onto engine. Reconnect fuel line and linkages properly.
- Replace air filter and cover. Make sure connections are secure.
- Add fresh fuel to tank and check for leaks at connections.
- Reconnect spark plug wire.
- Start trimmer and test performance. May need adjustment.
- Let run for 5 minutes to confirm proper carburetor operation.
4String Trimmer Recoil Starter
Common Solution
Repair Instructions:
The recoil starter assembly connects to the crankshaft to turn the engine over. If it's broken, the engine won't start up. Take the starter off and check if it works right. When pulling the rope, tabs on the pulley and cam should grab the engine hub and make the engine spin. Letting go should make the tabs retract as the rope rewinds onto the pulley. If the recoil starter isn't engaging or recoiling properly, replace it. The starter assembly has to engage and turn the engine to start it. Inspect how the parts move when pulled and released. The tabs and pulley must interact with the engine hub as intended. If the recoil motions aren't happening correctly, the starter needs a swap out. Proper engagement and retraction are key for the rope starter to turn over and start the engine.
How to Replace String Trimmer Recoil Starter
- Disconnect the spark plug wire from the spark plug to prevent accidental starting.
- Remove trimmer head and any covers necessary to access recoil starter. Consult owner's manual.
- Mark orientation of recoil on trimmer housing before removing. This will help during reinstallation.
- Remove recoil mounting bolts using appropriate sized wrench or socket.
- Remove recoil assembly from trimmer, making note of spring orientation.
- Install new recoil starter in same orientation as old one. Line up mounting holes.
- Replace mounting bolts to secure new recoil starter. Do not overtighten.
- Reattach recoil starter rope to new pulley, maintaining proper spring tension.
- Replace trimmer head and any covers removed earlier in process.
- Reconnect spark plug wire to spark plug when complete.
- Test recoil starter operation several times to verify proper function and spring tension.
- Check recoil operation regularly to ensure starter rope retracts smoothly.
5String Trimmer Fuel Filter
Common Solution
Repair Instructions:
The fuel filter might be choked up. This is usually caused by leaving old gas in the Trimmer Plus string trimmer. Over time, some ingredients in the fuel can evaporate. This leaves a thicker, stickier substance behind. That sticky stuff can clog the fuel filter and stop the engine from starting. If old gas was sitting in there, drain the tank fully. Then replace the fuel filter. Letting gas sit turns it thick and gummy. Those deposits block proper fuel flow through the filter. Try draining out all old gas first. But if it was really stale, the filter may be too gummed up internally. Swapping in a fresh, clean filter allows good fuel flow to the engine again. Removing old gas and replacing a clogged filter can get an engine starting and running properly.
How to Replace String Trimmer Fuel Filter
- Locate the fuel filter. It is typically found inline along the fuel line. Refer to your owner's manual for the specific location.
- Pinch off the fuel line on both sides of the filter to prevent fuel from draining out when removing.
- Use pliers to open and slide clamps off the fuel line ends on the old filter.
- Remove the old fuel filter from the fuel line. Catch any dripping fuel with a rag.
- Inspect the fuel lines for cracks or damage. Replace if needed.
- Slide clamps over the ends of the new replacement fuel filter.
- Attach the fuel lines securely onto both ends of the new filter.
- Slide clamps back over connections and use pliers to tighten.
- Check for fuel leaks by gently pressing on filter to prime system. Repair any leaks found.
- Start trimmer and let run for several minutes keeping an eye out for leaks.
- Replace filter periodically as part of routine maintenance.
6String Trimmer Spark Arrestor
Common Solution
Repair Instructions:
The spark arrestor is a little screen that stops sparks from coming out of the engine. Over time, the screen can get clogged with carbon buildup. If it gets choked with gunk, the engine might not start. To fix this, take the spark arrestor off and scrub it clean with a wire brush. You could also just replace the clogged spark arrestor with a new one. That small mesh screen is there to contain any hot sparks inside the engine. But carbon deposits from use can plug it up. A spark arrestor blocked with debris can prevent the engine from starting properly. Try brushing it out first to unclog it. Or just swap in a fresh new spark arrestor screen. An unobstructed arrestor allows the engine to start and run without dangerous sparks shooting out.
How to Replace String Trimmer Spark Arrestor
- Locate the spark arrestor on the muffler exhaust port. It may be held on by a few screws.
- Allow muffler to fully cool before proceeding. The muffler will be very hot from operation.
- Remove any protective heat shields or covers to access the spark arrestor.
- Remove the mounting screws to detach the old spark arrestor from the muffler.
- Clean the muffler exhaust port with a wire brush to remove carbon deposits.
- Insert the new spark arrestor into the exhaust port aligned properly.
- Replace mounting screws to secure the new arrestor. Do not overtighten.
- Replace heat shields or covers removed earlier to access the muffler.
- Start trimmer and test operation for several minutes. Ensure no exhaust leaks at arrestor.
- Allow muffler to fully cool before doing any further work.
- Replace spark arrestor periodically to prevent clogging.
7String Trimmer Rewind Spring
Common Solution
Repair Instructions:
When you pull and let go of the starter rope, the rewind spring makes the rope recoil back onto the pulley. If that spring breaks, the rope won't snap back into place. This prevents the engine from starting up. If the rewind spring is busted, it needs replacement. Many rewind springs can be swapped out by themselves. But it might be easier to replace the whole starter assembly. That spring is what retracts the rope after pulling it to start the engine. Check if the spring is cracked or stretched out at all. If broken, the rope will just hang loose instead of rewinding. Putting in a new spring or starter ensures the recoil action works to get the engine going. The rewind spring is key for allowing repeated starting attempts.
How to Replace String Trimmer Rewind Spring
- Disconnect the spark plug wire from the spark plug to prevent accidental starting.
- Remove spool cover to access rewind spring assembly. May need to remove trimmer head.
- Take note of how the rewind spring is assembled and oriented. This will help during reassembly.
- Carefully release spring tension and remove the rewind spring. Caution - it may unexpectedly release.
- Clean pulley and housing where spring is mounted using compressed air or rag. Remove any debris.
- Install new rewind spring per manufacturer's instructions. Recreate same tension and orientation.
- Slowly retract spring and attach spring end to rewind pulley. Confirm it retracts properly.
- Replace spool cover and trimmer head, making sure parts are properly seated.
- Reconnect spark plug wire to spark plug.
- Start trimmer and test rewind starter operation several times to confirm proper spring function.
- Check rewind regularly to ensure spring has proper tension. Replace again if loosening occurs.
8String Trimmer Rewind Pulley and Spring
Common Solution
Repair Instructions:
The issue may be a broken rewind spring. When you pull and release the starter rope, that spring makes the rope snap back onto the pulley. If the spring is busted, the rope won't recoil into place. This prevents the engine from starting up. Check if the rewind spring is cracked or stretched out. If broken, it needs a swap out. Many rewind springs can be replaced individually. But it might be easier to replace the whole pulley and spring piece. That spring is key for retracting the rope after pulling to start. If it's broken, the rope will just hang loose instead of rewinding. Replacing the faulty spring or the full assembly ensures the recoil action works to start the engine. The rewind spring has to work right to allow repeated starting attempts.
How to Replace String Trimmer Rewind Pulley and Spring
- Disconnect the spark plug wire from the spark plug to prevent accidental starting.
- Remove any covers or housings around the rewind assembly. Consult your owner's manual.
- Release the spring tension carefully and detach the spring from the old pulley. The spring may unexpectedly release.
- Remove the rewind pulley mounting bolt using the appropriate-sized wrench or socket.
- Remove the old pulley from the trimmer shaft. Make note of the pulley's orientation on the shaft.
- Clean the shaft and housing with compressed air or a rag. Remove any dirt or debris.
- Install the new rewind pulley in the same orientation as the old one. Replace the mounting bolt.
- Attach the new rewind spring per the manufacturer's instructions. Recreate the same spring tension.
- Retract the spring and connect its end to the new pulley. Confirm the pulley retracts properly.
- Replace any housing covers removed earlier to access the assembly.
- Reconnect the spark plug wire to the spark plug when finished.
- Test the rewind starter several times to verify proper operation. Adjust spring if needed.
9String Trimmer Recoil Starter Pulley
Common Solution
Repair Instructions:
The recoil starter pulley is what winds the starter rope back up when not in use. If the pulley breaks or gets jammed, it can't retract the rope back in. This prevents the engine from starting. Check if the recoil pulley is damaged or stuck from rope debris. If the pulley is busted, you'll need to replace it. The starter pulley has to be able to spin freely to rewind the starter rope after each pull. Look it over for any cracks, seized bearings, or material wrapped around it. Any of that could make the pulley non-functional. Without the pulley retracting the rope properly, the engine won't start up. Swapping in a new recoil starter pulley will ensure it can smoothly wind the rope back in for the next start attempt.
How to Replace String Trimmer Recoil Starter Pulley
- Disconnect the spark plug wire from the spark plug to prevent accidental starting.
- Remove trimmer head and any covers necessary to access recoil starter. Consult owner's manual.
- Mark current pulley orientation on the starter housing before removing. This will help with reassembly.
- Loosen pulley retainer screw and remove old pulley. Be careful not to lose retainer parts.
- Clean pulley retainer and housing using compressed air or rag to remove debris.
- Install new pulley in same orientation as old one. Make sure it spins freely on the starter shaft.
- Replace pulley retainer and tighten screw to secure the new pulley per the manufacturer's instructions. Do not over tighten.
- Check starter operation by pulling rope several times. The pulley should rotate smoothly.
- Reattach starter rope to new pulley while maintaining proper spring tension.
- Replace trimmer head and any covers removed earlier to access the assembly.
- Reconnect spark plug wire when complete.
- Test starter several times to confirm smooth operation of new pulley/rope.
10String Trimmer Air Filter
Common Solution
Repair Instructions:
The issue could be a clogged air filter. When the filter gets choked with dirt, the engine doesn't get enough air. Too little air and too much fuel stops the engine from starting up. Check if the air filter is really dirty and plugged. If it's clogged, you'll need to swap in a new filter. That filter is crucial for proper air intake. Without air flow, the fuel mixture will be off and the engine won't start. Look at the filter to see if it's covered in debris and needs replacement.
How to Replace String Trimmer Air Filter
- Locate air filter housing on trimmer, usually near the carburetor. Consult owner's manual for location.
- Open air filter cover or access panel on housing to reveal filter.
- Remove old air filter from housing. Note orientation for reinstallation. Discard old filter.
- Clean inside of air filter housing using a rag or compressed air to remove debris.
- Check new filter gasket and replace if worn out or damaged.
- Install new air filter in housing oriented correctly based on old filter position.
- Make sure filter is fully seated in housing.
- Close access panel or air filter cover. Tighten any clamps or screws removed earlier.
- Check cover is installed properly with no gaps, leaks or misalignment.
- Start trimmer and test operation. Allow engine to run for several minutes.
- Check air filter periodically as part of routine maintenance. Replace when dirty.
