If your Sun Joe SJH904E will not start, runs slowly, becomes noisy, or has hot blades, use the checks below. Start with the power connection and the correct safety-switch sequence, then inspect and lubricate the blades only after disconnecting the tool.
Model Covered and Power Type
Before Troubleshooting
Troubleshooting Steps
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Check the Extension-Cord Connections
Confirm that the extension cord is fully connected to the trimmer's appliance cord and to a working outlet. Route the cord through the rear-handle cord restraint so the connection cannot pull apart during use.
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Inspect the Cord and Power Source
Use an outdoor-rated extension cord and inspect its plug, receptacle, and insulation. Do not use a cut, cracked, loose, scorched, or otherwise damaged cord. Test the outlet with another device if needed.
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Confirm the Cord Gauge and Length
Use at least a 16 AWG extension cord for lengths up to 50 ft (15 m), or at least a 14 AWG cord for lengths over 50 ft through 100 ft (15–30 m). Do not use an extension cord longer than 100 ft (30 m).
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Use the Correct Start Sequence
In handheld mode: Hold the trimmer with both hands. Press and hold the hand safety switch on the front handle. Press and hold the safety lock button, then squeeze the trigger. Once the motor starts, release the safety lock button while continuing to hold both the hand safety switch and trigger.
In pole mode: Hold the trimmer with both hands. Press and hold the safety lock button on the rear handle, then squeeze the trigger. Once the motor starts, release the safety lock button and continue holding the trigger.
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Clean Slow, Noisy, or Hot Blades
Unplug the tool and wait for the blades to stop. Use a dry towel or brush to remove clippings and debris from the blades and ventilation openings. Do not spray the tool with water or use solvents.
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Lubricate the Blades
With the trimmer unplugged and lying on a flat surface, apply lightweight machine oil along the edge of the top blade. Lubricate the blades before and after each use. Never apply oil while the trimmer is running.
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Inspect for Blade or Hardware Damage
Check for a bent blade or blade support, bent or damaged teeth, corrosion, or visibly loose blade hardware. Do not operate the trimmer with dull, bent, damaged, or unsecured blades. Do not attempt to straighten the blades or teeth; keep the unit unplugged and contact support.
When to Stop Using the Trimmer
- The power cord, extension cord, plug, switch, or housing is damaged.
- The blades, blade support, teeth, or blade hardware are bent, broken, loose, or severely corroded.
- The blades remain unusually hot, noisy, or slow after cleaning and lubrication.
- The tool produces smoke, sparks, a burning odor, excessive vibration, or an unusual grinding sound.
- The unit still does not start after the power and safety-control checks.
Escalation Path
If the issue continues, contact Shop Joe Customer Support. Have the model number, serial number, extension-cord length and gauge, operating configuration, and a description of the symptoms ready.