String Trimmer Parts

String Trimmer Carburetor, Fuel Line, and Spark Plug Parts

String trimmers fail most often in the fuel system and ignition. A clogged carburetor from ethanol-damaged fuel is the #1 reason a trimmer won't start or runs rough. Fuel lines crack and primer bulbs lose suction. Spark plugs foul from old gas or improper mix ratios. The good news: these are inexpensive fixes, and OEM carburetors, fuel lines, and spark plugs keep your, or running strong.

Trimmer heads and spools are the consumable you'll replace most often — line runs out, the spool gets jammed, or the bump mechanism wears. Load the correct line diameter for your head, and your trimmer feeds smoothly every time. Recoil starters, throttle cables, and air filters round out the parts that keep your trimmer dependable season after season.

• Carburetor and rebuild kits: hard start, runs lean/rich, won't idle
• Primer bulbs: cracked, won't draw fuel to carb
• Fuel lines and filters: cracked from ethanol damage, kinked, clogged
• Spark plugs: fouled plug, wrong heat range for your engine
• Trimmer heads and spools: line won't feed, spool jammed, bump mechanism worn
• Recoil starter assemblies: pull cord stuck, won't recoil smoothly
• Air filters: foam or paper; clogged filter restricts airflow

Find your string trimmer model number on the engine or equipment label, then use Repair Clinic's parts lookup to get the exact OEM replacement. We carry, and more.

String Trimmer Parts — Frequently Asked Questions

Why won't my string trimmer start, and how do I know if it's the carburetor?

A trimmer that won't start or is hard to start almost always points to the carburetor. Ethanol fuel corrodes the carburetor's float, needle, and jets over time — especially if the trimmer sits unused for a season. You'll smell stale fuel, see white deposits inside the carb bowl, or the primer bulb will be soft and won't build pressure. A carburetor rebuild kit ($10 to $20) often fixes it. If the carb is severely corroded, replace the whole carburetor. Always verify your model number — FS55 and FS90 carburetors are different, for example.

What's the correct trimmer line diameter for my trimmer head, and how do I load it?

Trimmer line diameter ranges from 0.065" to 0.095" depending on your head and engine size. Check your trimmer head or owner's manual for the correct size — loading the wrong diameter causes feeding problems. Most OEM trimmer heads have a bump mechanism: when you tap the head on the ground, it advances a fresh length of line. Load line into the spool channels as directed, wind it tight, and snap the spool back on. Aftermarket heads have higher failure rates; an OEM or head prevents most feeding headaches.

My trimmer won't stay running even though it starts. What parts should I check first?

If it starts but won't idle or dies under load, the carburetor is still the prime suspect — but also check the spark plug and air filter. A fouled spark plug will cause stalling; a clogged air filter restricts airflow and makes the mix run too rich. Replace the spark plug first ($2 to $5), then the air filter ($5 to $15), then rebuild or replace the carburetor. If you're using old fuel or old fuel-oil mix, drain the tank and refill with fresh mix. Most string trimmers need a 50:1 or 40:1 gasoline-to-oil ratio — verify yours in the manual.

How do I find my string trimmer model number, and why does it matter?

Your model number is stamped on the engine block or printed on a label near the fuel cap or handle. For look for the six-digit model (FS45, FS55, FS90, FS131). For it's usually on a decal near the air filter (128LD, 525LS). For or, check the base of the shaft or handle. The model number tells you the exact carburetor, ignition module, and fuel line routing — parts that look similar but fit differently across models. Always enter your full model number into the Repair Clinic parts lookup to avoid ordering the wrong part.

Find and Order String Trimmer Parts Online Today

Keep your string trimmer in top condition with our full inventory of replacement parts. Whether you're a homeowner or professional technician, you can find the right parts, weed wacker parts, and string trimmer repair parts conveniently online. Our user-friendly site allows you to quickly search by model or part number, ensuring you find genuine, compatible parts. Take advantage of our same-day shipping, so your order arrives just in time for your next project. We also offer a No-Hassle 365-Day Returns policy and a Price Match Guarantee for added confidence. Common issues, like a string trimmer that won't start or runs rough, can be solved by replacing faulty spark plugs, clogged carburetors, or air filters. For more repair tips and guidance, visit our String Trimmer Repair Help page. Browse our inventory and order your string trimmer parts online today to maintain your equipment's performance.

Model Number Basics for String Trimmer Owners

Check the label on your string trimmer's main housing near the engine or along the shaft. Depending on the brand, the model number may also appear on the engine cover, near the fuel cap, or by the handle. Look for a combination of letters and numbers, and copy the complete number, including any suffixes. Enter it in the model number search to pull up the parts matched to your unit. The model number filters the entire String Trimmer catalog, so you can narrow every associated part category to parts made for your specific equipment. That means fewer wrong orders and a faster repair.