Owner’s manual
How to replace line on Craftsman gas trimmer?
To replace trimmer line on your Craftsman 316791841 gas trimmer, we install new line through the correct holes in the cutting head, pull it fully through the positioning tunnels, and make both sides the same length. Follow the glide plate arrows for the line size.
Steps to replace the line (Hassle-Free line replacement)
- Turn the trimmer off and let the engine cool completely.
- Remove the old line and the line glide plate from the cutting head.
- Clean the entire surface of the cutting head.
- Reinstall the line glide plate; align the arrow on the glide plate to the correct setting for your line size.
- Insert both ends of the new line through the proper holes in the side of the cutting head.
- Pull the line so it seats against the hub and fully extends through the positioning tunnels.
- Confirm both line ends are the same length (this helps prevent vibration and tangling).
Glide plate arrow settings (quick reference)
| What you are installing | Glide plate arrow alignment | Why it matters |
|---|---|---|
| Medium (red) or large (black) line | A | Keeps the line routed correctly for the intended diameter |
| Smaller than medium (red) line | B | Prevents poor feeding and uneven wear |
Tips to prevent tangling and vibration
- Keep the two line ends equal length after threading.
- Make sure the line is fully seated in the positioning tunnels before trimming.
- Replace line if it wears unevenly; uneven line commonly causes excessive vibration.
- Avoid forcing the line into hard objects (walls, fence posts) to reduce breakage.
Why it matters
Correctly routing the line through the cutting head and matching both sides in length helps the head feed properly, reduces line breakage, and prevents uncomfortable vibration during normal trimming.
For the exact line routing diagrams and glide plate details for model 316791841, use the 316791841 owner's manual. If you also need tune-up parts while you are servicing the trimmer, we stock items like the spark plug 794-00082 and the mtd lawn and garden equipment engine air filter 753-05254, and you can search more parts by model on Sears PartsDirect.
Last updated: February 2026
What size is the fuel line on a Craftsman trimmer?
For the Craftsman gas trimmer model 316791841, the correct fuel line size is the size that matches your trimmer’s tank grommet and the carburetor or primer fittings. We size fuel line by measuring the inside diameter (ID) and outside diameter (OD) of the original line and confirming the routing in the 316791841 owner's manual.
How to measure the fuel line correctly
Measure the old line before you remove it (or bring a short sample to match).
- Measure ID first; it must seal tightly on the fuel filter nipple and carburetor or primer ports
- Measure OD next; it must pass through the tank opening and grommet without leaking
- Replace line that is hard, cracked, swollen, or sticky
- Cut ends square so they seal and do not pull air
- Route the line so it cannot kink when the tank is reinstalled
Typical fuel line sizing on small gas trimmers (use as a starting point)
Most small 2-cycle and 4-cycle trimmers use two different line sizes: a smaller return line and a larger supply line. Use this table as a baseline, then match to your original line.
| Line role | Where it runs | Typical ID range | Typical OD range |
|---|---|---|---|
| Supply line (larger) | Tank fuel filter to carb | 1/8 to 3/16 in | 3/16 to 1/4 in |
| Return line (smaller) | Primer back to tank | 3/32 to 1/8 in | 5/32 to 3/16 in |
Why it matters
If the ID is too large, the trimmer pulls air instead of fuel; that causes hard starting, surging, and stalling. If the OD is too large, the line can leak at the grommet or get damaged during installation.
If you are doing a tune-up at the same time, replacing the spark plug 794-00082 often helps starting and idle quality.
You can order replacement parts for model 316791841 from the parts list for this model, or search by model number on Sears PartsDirect.
Last updated: February 2026
How do I find the model number on my 316791841?
The model number is printed on the product identification label on your Craftsman gas trimmer; for this unit it appears as 316.791841 in the documentation. Use the label (not the engine casting) when ordering parts or checking the correct manual, such as the 316791841 owner's manual.
Where to look on the trimmer
On Craftsman gas trimmers like model 316791841, the ID label is typically on the shaft or near the engine housing where it stays readable during normal use.
- Check the shaft/tube near the handle or coupler area
- Check the engine housing (outer shroud), usually on a flat spot
- Look for a sticker or plate that says Model No.
- Wipe off dirt and grass; use a flashlight to read small print
- Write down the full model number exactly as shown (including dots if present)
What to record (so parts match)
When you find the label, capture these details before you shop for parts like a spark plug or carburetor.
| Label item | What it’s used for | Example for this trimmer |
|---|---|---|
| Model number | Ensures diagrams and parts fit | 316.791841 |
| Part number | Identifies a specific replacement part | 753-05784 (spark plug) |
| Serial number | Helps identify production run details | Varies by unit |
Why it matters
Craftsman trimmers can look similar across multiple model numbers, but parts like the carburetor, ignition coil, and fuel tank can differ. Using the exact model number keeps you matched to the correct parts list and diagrams for 316791841.
Last updated: March 2026
