Homelite ST-155 trimmer Parts

Yes, you can usually run .095-inch trimmer line in a trimmer set up for .080-inch line, but on a Homelite ST-155 it increases load on the engine and cutting head; that can reduce RPM, make bump-feed less reliable, and increase vibration. Use it only if the head and eyelets accept it and performance stays stable.

Quick fit check (before you spool it)

• Confirm the cutting head is rated to accept .095 line; many heads are limited to .080.
• Make sure the line passes smoothly through the eyelets without forcing.
• Wind the spool evenly and do not overfill it; overfilling causes binding.
• If the head uses bump-feed, verify it can advance thicker line without sticking.
• Stop if you notice bogging, excessive vibration, or the clutch slipping.

What changes when you go thicker

Thicker line cuts heavier weeds and lasts longer, but it also takes more power to spin.

Line size	Best for	Typical tradeoff
.080 in	Grass, light trimming	Faster RPM, easier feed
.095 in	Heavier weeds, edging in tough growth	More drag, harder feed, more fuel use

How to test it safely on the ST-155

• Start with a short length of .095 and trim for 1 to 2 minutes.
• If the head will not feed, switch back to .080 rather than forcing the bump mechanism.
• If the engine bogs, return to .080; running overloaded accelerates wear.
• While you are there, replace worn hardware that can worsen vibration, such as a washer 84065 or a screw 82540 if your originals are stripped.

Why it matters

Line diameter affects engine load, clutch engagement, and cutting head feed. Using the thickest line the head is designed for gives you better cut quality without sacrificing reliability.

You can order replacement parts for your Homelite ST-155 from the parts list for this model, or search by model number on Sears PartsDirect.

Last updated: February 2026

For the Homelite ST-155 gas line trimmer, the best trimmer line is the thickest diameter your trimmer head is designed to handle; thicker line lasts longer in heavy weeds, while thinner line cuts cleanly with less engine load for routine trimming.

Choosing the right line (what works best in real yards)

Use this quick guide based on what you cut most often:

• Light grass and edging: 0.065 in to 0.080 in line for smooth cutting and easy feed
• Mixed grass and moderate weeds: 0.080 in to 0.095 in line for better durability
• Thick weeds and tough growth: 0.095 in line (only if your head supports it)
• Square or twisted line: better bite on weeds, often a little noisier
• Round line: quieter and smoother, best for regular lawn maintenance

Fit check: diameter matters more than brand

If the line is too thick, it can jam the spool, stop feeding, and make the engine bog down. If it is too thin, it wears quickly and breaks more often.

Quick comparison

What you want	Best choice	Tradeoff
Long life in weeds	Thicker line (0.080 in to 0.095 in)	More load on the engine
Clean edging	Thinner line (0.065 in to 0.080 in)	Shorter wear life
Aggressive cutting	Square or twisted profile	Can be louder

Tips to reduce breakage and feeding problems

• Keep the line dry and clean; dirt and grit accelerate wear
• Avoid “sawing” into fences, rocks, and concrete; that instantly shortens line life
• Replace worn trimmer head hardware so the spool stays aligned; a missing fastener can cause poor feed (for example, a correct-fit screw 82540)
• If the engine struggles, step down one line size before chasing carburetor or ignition issues

Why it matters

Using the correct line diameter helps your ST-155 maintain RPM, reduces stalling, improves cut quality, and prevents premature wear on the trimmer head and drive components.

If you are stocking up on maintenance items for this model, you can order parts from the list for your ST-155, or search by model number on Sears PartsDirect.

Last updated: February 2026

For the Homelite ST-155 gas line trimmer, we run a 50:1 gasoline-to-2-cycle oil fuel mix (50 parts fresh unleaded gas to 1 part 2-cycle oil). This ratio helps protect the 2-cycle engine from overheating, scoring, and premature wear.

Quick mix chart (50:1)

Use this as a fast reference when mixing fuel for your ST-155.

Gasoline amount	2-cycle oil needed (50:1)
1 gallon	2.6 fl oz
2 gallons	5.1 fl oz
2.5 gallons	6.4 fl oz
5 gallons	12.8 fl oz

How we recommend mixing fuel

• Use a clean, approved fuel can (not the trimmer tank) for mixing.
• Add about half the gasoline first.
• Measure and add the correct amount of 2-cycle oil.
• Add the remaining gasoline, then cap and shake to blend.
• Mix only what you will use in about 30 days for best starting and performance.

If the trimmer runs poorly after mixing

A correct mix ratio is step one; if it still bogs, surges, or won’t stay running, these checks usually fix it:

• Replace a dirty or restricted fuel/air filter (a clogged filter leans the mix and hurts power).
• Inspect the primer bulb for cracks or stiffness and replace if it won’t prime.
• Drain old fuel and refill with a fresh 50:1 mix.
• Check for loose fasteners that can cause air leaks or vibration issues.

Parts that commonly relate to fuel and starting

Symptom	Part to consider
Hard starting, won’t prime	Primer bulb UP04802
Runs lean, lacks power	Filter 49422 or filter PS98913

Why the 50:1 ratio matters

A 2-cycle trimmer depends on oil in the fuel for lubrication. Too little oil increases friction and heat; too much oil can foul the spark plug and smoke excessively. Keeping a consistent 50:1 mix gives the ST-155 reliable starting and longer engine life.

Ordering parts

If you need replacement parts for your Homelite ST-155 (like a primer bulb or filter), we list compatible options on this model’s parts list; you can also search by model number on Sears PartsDirect.

Last updated: February 2026