Owner’s manual
What is the fuel mix for a Craftsman gas trimmer?
For the Craftsman gas line trimmer model 358791030, we use a 40:1 gasoline-to-2-cycle oil mix. That equals 3.2 fl oz of 2-cycle (air-cooled) oil per 1 gallon of unleaded gasoline; mix it in an approved fuel container before filling the tank (see the 358791030 operator's manual).
Quick mix chart (40:1)
| Gasoline amount | 2-cycle oil to add |
|---|---|
| 1 gallon | 3.2 fl oz |
| 1/2 gallon | 1.6 fl oz |
| 1 quart | 0.8 fl oz |
How we recommend mixing fuel
- Use fresh unleaded gasoline in a clean, approved fuel can
- Add the measured 2-cycle air-cooled oil first or second (either works)
- Cap the container and shake briefly to blend thoroughly
- Fill the trimmer outdoors and wipe up any spills
- Move the trimmer at least 10 feet away from the fueling spot before starting
Oil type and what to avoid
Use a good-quality synthetic 2-cycle air-cooled engine oil. Avoid these because they can damage a 2-cycle trimmer engine:
- Automotive (4-cycle) engine oil
- Marine 2-cycle oil
- Old or contaminated fuel mix
Why it matters
A correct 40:1 mix keeps the 2-cycle engine properly lubricated. Too little oil can score the piston and cylinder; too much oil can cause heavy smoke, carbon buildup, and poor running.
Last updated: January 2026
How to replace line on Craftsman gas trimmer?
To replace the cutting line on your Craftsman 358791030 gas line trimmer, switch the unit OFF, disconnect the spark plug wire, remove the spool, then reload it with two equal lengths of 0.080-inch (2 mm) round line and reinstall the spool. Use the steps in the Craftsman 358791030 owner's manual.
Step-by-step: reload the bump head line
- Move the ON/OFF switch to OFF.
- Disconnect the spark plug wire before maintenance.
- Remove the spool by firmly pulling on the tap button.
- Clean the hub and spool so the line feeds smoothly.
- Cut two lengths of 12-1/2 ft (3.8 m) of 0.080 in (2 mm) round line.
- Insert each line end about 1/2 in (1 cm) into the small holes inside the spool.
- Wind the line evenly and tightly in the direction of the arrow on the spool.
- Push the line into the spool notches, leaving 3 to 5 in (7 to 12 cm) unwound.
- Feed the line ends through the exit holes in the hub and reinstall the spool.
Quick specs for model 358791030
| Spec | What to use |
|---|---|
| Line diameter | 0.080 in (2 mm) |
| Line shape | Round |
| Line length | Two pieces, 12-1/2 ft each |
| Prewound option | Spool #71-85819 |
Why it matters
This model is designed to advance 0.080-inch round line correctly. Using the right diameter and winding it evenly prevents tangles, improves bump-feed performance, and reduces wear on the trimmer head and line limiter.
After you reload: line advance tip
- Run at full throttle.
- Hold the head parallel to the ground.
- Tap the head lightly on grass; it advances about 2 in (5 cm) per tap.
- Avoid tapping on concrete or asphalt to reduce head wear.
Last updated: January 2026
Is the .095 trimmer line good?
Yes, 0.095-inch trimmer line is a good heavy-duty choice for thicker weeds, but it is not the correct size for Craftsman model 358791030. Our manual for this model specifies 0.080-inch (2 mm) round line; using 0.095 can prevent proper bump-feed and increase wear.
Correct line spec for Craftsman 358791030
The trimmer head on this model is designed to advance a specific diameter and shape of line.
- Use 0.080 inch (2 mm) diameter line
- Use round line so it advances properly
- Keep the shield installed so the line limiter controls length
- Keep line at the proper length (do not run extra-long tails)
- Never use wire, rope, or string
For the exact wording and safety notes, follow the 358791030 owner's manual.
0.080 vs 0.095: what changes
0.095 line is typically more durable, but it is also harder for smaller heads to feed and spin efficiently.
| Line diameter | Best use | What you may notice on 358791030 |
|---|---|---|
| 0.080 in (specified) | General trimming and edging | Smooth feed, normal RPM, less vibration |
| 0.095 in (oversize) | Heavy weeds on trimmers designed for it | Poor feed, bogging, extra head wear |
If you already tried 0.095 and it will not feed
Switch back to 0.080 round line and check these basics:
- Bump-feed with the engine at full throttle
- Tap the head on grass, not concrete or asphalt
- Rewind line neatly (no crossing or binding)
- Clean the spool and eyelets (remove melted line debris)
Why it matters
Using the specified line size helps the bump-feed system work correctly and reduces stress on the trimmer head, clutch, and engine, while also improving cut quality and safety.
Last updated: January 2026
