Craftsman 316731930 gas trimmer Parts

For the Craftsman 316731930 gas trimmer, use a 40:1 fuel mix (40 parts fresh unleaded gasoline to 1 part 2-cycle engine oil). This ratio helps the 2-cycle engine lubricate properly, start easier, and avoid plug fouling and premature wear.

• Use a clean, approved fuel can (not the trimmer tank) for mixing.
• Add about half the gasoline first, then add the measured 2-cycle oil.
• Cap and shake to blend, then add the remaining gasoline and shake again.
• Use fresh fuel; old fuel is a common cause of hard starting and poor acceleration.
• Store mixed fuel tightly sealed and away from heat sources.

• Use 2-cycle air-cooled engine oil (often labeled for trimmers, blowers, and chainsaws).
• Use fresh unleaded gasoline (most owners use 87 octane).
• Avoid automotive 4-cycle oil; it is not designed to mix with gasoline.
• Avoid guessing the ratio; measure the oil every time.

A 2-cycle Craftsman trimmer relies on the oil in the fuel for lubrication. Too little oil can score the cylinder and piston; too much oil can cause heavy smoke, carbon buildup, and spark plug fouling.

For model-specific fuel and maintenance notes, follow the 316731930 owner’s manual.

Last updated: January 2026

If your Craftsman gas trimmer model 316731930 is flooded, we clear it by stopping fuel flow, opening the throttle, and pulling the starter to purge excess fuel, then restarting with the correct choke position. Use the starting steps in the 316731930 owner's manual as your baseline.

• Move the switch to OFF and set the trimmer on a flat surface.
• Set the choke to RUN/OFF (not FULL CHOKE).
• Hold the throttle wide open (this lets more air in).
• Pull the starter rope 6 to 10 times to clear the cylinder.
• Turn the switch to ON, keep throttle open, and pull until it tries to start.
• Once it fires, feather the throttle for 10 to 20 seconds so it stays running.

A wet plug will not ignite fuel reliably. Remove it, dry it, and reinstall; replace it if it is fouled.

If you need a replacement, use the exact spark plug listed for this model: spark plug 794-00082.

A clogged air filter can make flooding easier and restarting harder. Inspect and replace if dirty: mtd line trimmer air filter 751-12833.

Flooding is simply too much fuel and not enough air for ignition. Clearing the cylinder and drying the spark plug restores the correct air-fuel balance so the ignition system can light the mixture.

Last updated: January 2026

For the Craftsman gas trimmer model 316731930, most owners use 0.095-inch (0.095 in) trimmer line for everyday trimming; it balances cutting power and feed reliability. For the exact line diameter and winding direction for your specific cutting head, follow the 316731930 owner's manual.

• 0.095 in: best all-around choice for thicker grass and light weeds
• 0.080 in: smoother feeding, good for lighter trimming (may wear faster)
• 0.105 in: heavy-duty cutting (can reduce runtime and may feed less smoothly)

Use these checks so the line feeds correctly and the bump head does not jam:

• Confirm your trimmer uses a bump-feed cutting head (common on gas trimmers)
• Match the diameter printed on the spool or in the manual
• Use round line for the most consistent feeding
• Replace line if it is brittle, flattened, or fused from heat
• Wind the line evenly and tight, without crossing wraps

Using the correct trimmer line size helps the cutting head feed smoothly, reduces engine load, and prevents premature wear on the drive shaft and head components.

Last updated: January 2026

On the Craftsman 316731930 gas trimmer, you replace the cutting line by opening the bump head, removing old line, and winding new line evenly so it does not overlap. Even, non-overlapping wraps feed smoothly and reduce tangles.

• Shut the engine off and let it cool completely.
• Disconnect the spark plug boot so the trimmer cannot start accidentally.
• Clean grass and debris off the cutting head and debris shield.
• Use the line diameter recommended in the 316731930 owner's manual.

1. Press the locking tabs (or remove the cap) to open the cutting head.
2. Pull out any remaining line and remove tangled pieces.
3. Cut two equal lengths of trimmer line (many heads use two pieces).
4. Insert the line ends into the eyelets or anchor holes in the spool.
5. Wind the line in the direction of the arrows on the spool.
6. Keep the wraps tight and side-by-side with no overlapping.
7. Feed the line ends through the head eyelets, reinstall the spool and cap, then pull the line to equal lengths.

• Line is fused or stuck: rewind with looser, even tension.
• Wrong line size: too thick binds; too thin can slip.
• Overfilled spool: remove some line and rewind.
• Dirty head: clean the spool cavity and eyelets.
• Worn head components: replace the head if the spool will not latch or the eyelets are damaged.

Correct line loading protects the cutting head, improves trimming performance, and prevents constant stoppages from tangles, poor feeding, and premature line breakage.

Last updated: January 2026