Owner’s manual
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Should I use 87 or 91 gas for lawn mower?
For the Craftsman 917377110 gas walk-behind lawn mower, we recommend using regular unleaded 87-octane gasoline for normal mowing. Higher octane (like 91) does not add power or improve reliability in small mower engines; using fresh fuel and the right storage practices matters far more. See the fuel guidance and safety notes in the Craftsman 917377110 owner's manual.
- Use fresh, regular unleaded 87 octane.
- Buy fuel in small quantities so it gets used within 30 days.
- Use a fuel stabilizer if the mower will sit more than a couple of weeks.
- Avoid old gas; stale fuel is a top cause of hard starting and rough running.
- Avoid overfilling the tank; leave room for expansion.
| Fuel choice | Best for | What you should expect |
|---|---|---|
| 87 octane (regular) | Everyday mowing | Normal starting, power, and engine life |
| 91 octane (premium) | Not needed unless the engine specifically calls for it | Typically no performance benefit |
Octane is mainly about knock resistance, not “cleaner burning” or “more power.” Most walk-behind mower engines are designed to run correctly on regular fuel; the bigger risk is stale gas causing carburetor varnish, hard starts, surging, and poor acceleration.
Try these checks before replacing parts:
- Drain old fuel and refill with fresh 87 octane.
- Inspect the air filter and spark plug condition.
- Check for fuel leaks and make sure the fuel cap vents properly.
- If the mower sat with fuel in it, clean the carburetor bowl and jets (common fix).
For off-season storage steps, follow how to winterize a lawn mower.
Last updated: January 2026
What is the average lifespan of a lawn mower?
Most gas walk-behind lawn mowers like the Craftsman 917377110 last 8 to 15 years with normal homeowner use; 10 years is a solid average when you keep up with oil changes, clean the deck, and keep the blade sharp. For model-specific maintenance intervals, use the Craftsman 917377110 owner's manual.
Lifespan depends heavily on engine hours, storage, and maintenance.
- Gas walk-behind mower: 8 to 15 years
- Electric walk-behind mower: 5 to 10 years (battery life is the limiter)
- Riding mower: 10 to 15 years
- Commercial-grade equipment: 15+ years with frequent service
| What you do | What it affects | Typical result |
|---|---|---|
| Change oil on schedule | Engine wear | Longer engine life, easier starting |
| Sharpen or replace blade | Cut quality, engine load | Cleaner cut, less bogging |
| Clean grass buildup under deck | Airflow, corrosion | Better discharge, less rust |
| Store with stabilized fuel | Carburetor/fuel system | Fewer no-start issues after storage |
If you see several of these at once, repairs can start to outweigh the value.
- Hard starting even after a tune-up (spark plug, fresh fuel, clean air filter)
- Excessive vibration (often from a bent blade or worn blade mount)
- Self-propel drive slipping or not pulling consistently
- Oil consumption, smoking, or loss of compression
- Rust-through or cracking around the deck and mounting points
These habits reduce strain on the engine, blade adapter, wheels, and drive system.
- Mow when grass is dry and not overgrown
- Keep the blade sharp; a dull blade forces the engine to work harder
- Clean the underside of the deck after mowing (with the spark plug wire disconnected)
- Use fresh gas and add fuel stabilizer before storage
- Inspect fasteners and wear items; replace damaged hardware promptly
A mower that is maintained typically lasts years longer, cuts cleaner, and avoids common failures like carburetor clogging, drive wear, and premature engine damage. That means fewer breakdowns mid-season and lower total cost of ownership.
Last updated: January 2026
Where can I find the Craftsman mower model number?
On a Craftsman gas walk-behind lawn mower like model 917377110, the model number is printed on the mower’s identification label (not on the engine label). Once you find it, match that exact number when ordering parts and using the Craftsman 917377110 owner's manual.
Check these common label locations on walk-behind mowers:
- On the rear of the deck near the discharge opening
- On top of the deck near the engine mounting area
- On the back flap area behind the engine (rear discharge models)
- On the handle bracket or height-adjuster area
- Under the grass bag door area (bagging models)
Many mowers have two different ID labels. For Sears PartsDirect parts lookup, use the mower model number.
| Label you find | What it identifies | When to use it |
|---|---|---|
| Mower model label (example: 917377110) | The mower chassis and drive system | Use for wheels, drive parts, deck parts, handle parts |
| Engine label (often on the blower housing) | The engine manufacturer and engine model/type | Use for engine-specific items like carburetor, ignition, air filter, starter |
- Wipe the area with a damp rag first; then dry it
- Use a flashlight at an angle to make faint printing easier to see
- Take a close-up photo and zoom in
- Write down the full model number exactly as shown (all digits)
The correct model number ensures you get parts that fit your exact Craftsman deck and drive configuration, such as the lawn mower drive control lever 532425662 or the correct wheel and chute components.
Last updated: January 2026
