🌿String Trimmer

SPARK PLUG FOULED

Husqvarna · 525LST 25.4 cc 17 in Gas String Trimmer

Husqvarna 525LST 25.4 cc 17 in Gas String Trimmer SPARK PLUG FOULED Error Fix: Spark Plug Fouled or Worn

The spark plug has carbon deposits, is wet-fouled from flooding, or has worn electrodes — remove and inspect; clean with a wire brush or replace; re-gap to manufacturer specification; replace the spark plug annually or whenever starting difficulty occurs; use the correct plug type specified in the 525LST manual

Medium severity2 fixes available

Quick Answer

Error SPARK PLUG FOULED on the Husqvarna 525LST 25.4 cc 17 in Gas String Trimmer means: Spark Plug Fouled or Worn. The top-ranked community fix is “Replace Ignition System Components for Persistent Spark Plug Fouling” (medium difficulty, ~45 min, DIY cost: $15-$30). 2 community-ranked fixes available below.

Published February 2026 · 2 fixes · string trimmer

Content is based on manufacturer service documentation, community repair experience, and OEM technical bulletins. Always verify with your owner's manual.Learn about our editorial standards.

When to Call a Professional

While many string trimmer repairs can be done safely at home, consider hiring a qualified technician if:

The repair involves electrical wiring, gas lines, or refrigerant
You've tried the top-ranked fix and the error persists
You smell gas, see sparking, or notice water leaking
The repair requires specialized tools you don't have
Your appliance is still under manufacturer warranty

Average professional repair cost for this issue: $100-$140.

Other Husqvarna Models with Error SPARK PLUG FOULED

350BT 50.2 cc Gas Backpack Leaf Blower

leaf_blower · 2 fixes

Other Husqvarna 525LST 25.4 cc 17 in Gas String Trimmer Error Codes

AIR FILTER

Air Filter Clogged

2 fixes

CLUTCH SLIP

Clutch Slipping Under Load

2 fixes

CORD WON'T RETRACT

Pull Cord Will Not Retract

Engine Dies at Idle

Exhaust Port or Muffler Blocked

Fuel System Leak

Trimmer Head Spins at Idle

2 fixes

HIGH VIBRATION

Excessive Vibration

2 fixes

People Also Ask About Husqvarna 525LST 25.4 cc 17 in Gas String Trimmer Error SPARK PLUG FOULED

What does error code SPARK PLUG FOULED mean on a Husqvarna 525LST 25.4 cc 17 in Gas String Trimmer?

Error code SPARK PLUG FOULED on the Husqvarna 525LST 25.4 cc 17 in Gas String Trimmer means: Spark Plug Fouled or Worn. The spark plug has carbon deposits, is wet-fouled from flooding, or has worn electrodes — remove and inspect; clean with a wire brush or replace; re-gap to manufacturer specification; replace the spark plug annually or whenever starting difficulty occurs; use the correct plug type specified in the 525LST manual

How do I fix error code SPARK PLUG FOULED on my Husqvarna 525LST 25.4 cc 17 in Gas String Trimmer?

The most successful fix is "Replace Ignition System Components for Persistent Spark Plug Fouling" (medium difficulty, ~45 minutes). Estimated DIY cost: $15-$30. HomeMD has 2 community-ranked fixes for this error.

Is error code SPARK PLUG FOULED on a Husqvarna 525LST 25.4 cc 17 in Gas String Trimmer serious?

This error is rated medium severity. It should be addressed soon, but your appliance may still function in a limited capacity.

Can I fix Husqvarna 525LST 25.4 cc 17 in Gas String Trimmer error SPARK PLUG FOULED myself?

Yes — the top-ranked community fix ("Replace Ignition System Components for Persistent Spark Plug Fouling") is rated medium difficulty and takes about 45 minutes. Tools needed: T25 Torx screwdriver, Spark plug socket wrench, Multimeter.

How much does it cost to repair Husqvarna 525LST 25.4 cc 17 in Gas String Trimmer error SPARK PLUG FOULED?

DIY cost: $15-$30. Professional repair typically costs $100-$140. Many homeowners save money by trying the top-ranked community fix first.

What other error codes does the Husqvarna 525LST 25.4 cc 17 in Gas String Trimmer have?

The Husqvarna 525LST 25.4 cc 17 in Gas String Trimmer has 8 other known error codes, including: AIR FILTER (Air Filter Clogged), CLUTCH SLIP (Clutch Slipping Under Load), CORD WON'T RETRACT (Pull Cord Will Not Retract), DIES AT IDLE (Engine Dies at Idle), EXHAUST CLOGGED (Exhaust Port or Muffler Blocked), and 3 more.

Which other Husqvarna models have the SPARK PLUG FOULED error?

Error code SPARK PLUG FOULED also appears on 1 other Husqvarna model: 350BT 50.2 cc Gas Backpack Leaf Blower. The fix may vary by model, so check each model's specific page for tailored repair steps.

What other error codes does the Husqvarna 525LST 25.4 cc 17 in Gas String Trimmer have?

The Husqvarna 525LST 25.4 cc 17 in Gas String Trimmer has 8 other known error codes:

AIR FILTER — Air Filter Clogged (2 fixes)
CLUTCH SLIP — Clutch Slipping Under Load (2 fixes)
CORD WON'T RETRACT — Pull Cord Will Not Retract (2 fixes)
DIES AT IDLE — Engine Dies at Idle (2 fixes)
EXHAUST CLOGGED — Exhaust Port or Muffler Blocked (2 fixes)
FUEL LEAK — Fuel System Leak (2 fixes)
HEAD SPINS AT IDLE — Trimmer Head Spins at Idle (2 fixes)
HIGH VIBRATION — Excessive Vibration (2 fixes)

Which other Husqvarna models have the SPARK PLUG FOULED error?

Error code SPARK PLUG FOULED also appears on 1 other Husqvarna model:

350BT 50.2 cc Gas Backpack Leaf Blower (leaf blower) · 2 fixes

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