Is it okay to put regular gas in a lawn mower?
Yes. For the Craftsman 917387620 gas walk-behind mower, we recommend fresh, clean, regular unleaded gasoline with a minimum of 87 octane; do not mix oil with the gasoline. For best starting and to protect the carburetor, use fuel that will be used within about 30 days (see the Craftsman 917387620 owner’s manual).
What fuel to use (and what to avoid)
- Use regular unleaded gasoline (87 octane or higher).
- Use fresh fuel; buy only what you can use in roughly 30 days.
- Do not mix 2-cycle oil into the gas (this mower uses straight gasoline).
- Avoid storing alcohol-blended fuel for long periods; it can attract moisture and contribute to fuel-system issues.
- Never refuel indoors; let the engine cool before adding fuel.
Storage tips if you will not mow for 30 days or more
If the mower will sit, we follow the storage guidance for this model:
- Add a quality fuel stabilizer to the tank (follow the stabilizer label mix ratio).
- Run the engine about 10 minutes to pull treated fuel into the carburetor.
- If you are not using stabilizer, drain the tank and run the engine until the fuel lines and carburetor are empty.
Quick comparison
| Situation | Best practice | Goal |
|---|---|---|
| Mowing weekly | Fresh 87+ octane regular | Reliable starts, steady power |
| Parking it for 1-4 weeks | Keep fuel fresh, top off as needed | Prevent stale fuel |
| Storing 30+ days | Stabilize and run, or drain and run dry | Reduce gum and varnish |
Why it matters
Most “won’t start” and “won’t stay running” complaints on walk-behind mowers trace back to stale fuel and carburetor varnish. Using regular gas is fine; keeping it fresh is what protects performance.
Related DIY help
Last updated: January 2026
What are the most common lawn mower repairs?
For the Craftsman 917387620 gas walk-behind mower, the most common repairs are basic maintenance and a few high-wear items: fixing no-start issues (fuel, spark, air), restoring cutting performance (blade and deck cleaning), and correcting vibration or control problems. The troubleshooting chart in the 917387620 owner’s manual is the best model-specific starting point.
Most common repairs (and what to check first)
- Won’t start: stale/empty fuel, dirty air filter, spark plug issues, or a disconnected spark plug wire.
- Runs rough or loses power: dirty air filter, old fuel, grass buildup under the deck, or oil level problems.
- Poor or uneven cut: dull/bent blade, uneven wheel height settings, or packed grass under the housing.
- Excessive vibration: loose or damaged blade, or a damaged blade adapter.
- Hard to pull starter rope: blade dragging in grass, operator control not held, or internal engine issues.
Parts that commonly solve these problems
If your symptoms point to a worn cutting or control component, these are common wear parts for this model:
- Lawn mower blade 532406713 (cut quality, vibration, mulching performance)
- Lawn mower blade adapter 581547901 (vibration, blade loosening, blade not spinning true)
- Walk-behind lawn mower engine cable 532176556 (operator presence control/zone control issues)
Quick symptom-to-fix guide
| Symptom | Most likely cause | First action we recommend |
|---|---|---|
| Won’t start | Fuel, air, spark | Drain old fuel, check air filter, inspect spark plug/wire |
| Uneven cut | Blade or wheel height | Set all wheels same height; inspect blade |
| Vibrates | Blade or adapter | Stop mower; inspect blade and adapter; tighten hardware |
| Loses power | Deck buildup or air filter | Clean underside of deck; service air filter |
Why it matters
These repairs prevent bigger failures. For example, running with a dull blade stresses the engine and leaves ragged grass tips, and mowing with grass packed under the deck can cause overheating and poor discharge.
Helpful DIY reading
For deck-related performance problems, we recommend how to keep grass clippings from sticking to a mower deck.
Last updated: January 2026
What kind of oil do I put in my Craftsman lawn mower?
For Craftsman model 917387620, we recommend SAE 30 engine oil when temperatures are above 32°F, and SAE 5W-30 when temperatures are below 32°F. This mower’s engine oil capacity is 20 oz, and we recommend changing oil every 25 hours of operation or each season (whichever comes first). See the 917387620 owner’s manual for the full oil and maintenance specifications.
Oil type and temperature guide
- Above 32°F: SAE 30
- Below 32°F: SAE 5W-30
- Use high-quality detergent oil with API service classification SF-SJ
- Check the oil level before each use (fill to the full line on the dipstick)
| Outdoor temperature | Recommended oil | Notes |
|---|---|---|
| Above 32°F | SAE 30 | Best for typical mowing-season temps |
| Below 32°F | SAE 5W-30 | Helps with cold-weather starting |
How much oil to add (capacity)
- Oil capacity for model 917387620 is 20 ounces
- If the engine is empty, add oil slowly and recheck the dipstick to avoid overfilling
- Keep the mower level when checking oil
Why it matters
Using the correct viscosity helps the engine maintain proper lubrication as temperatures change. That reduces wear, helps prevent smoking from overfilling, and supports consistent starting and cutting performance.
Last updated: January 2026





