Owner’s manual
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Should I use 87 or 91 gas for lawn mower?
For the Craftsman gas walk-behind mower model 917378501, use 87-octane (regular) unleaded gasoline for normal operation. Higher octane (like 91) does not add power in small mower engines; it is mainly for engines designed for it. Follow the fuel guidance in your 917378501 owner's manual.
What to use (and what to avoid)
- Use: Fresh 87-octane unleaded gasoline.
- Avoid: Old gas (more than about 30 days without stabilizer).
- Avoid: Gas contaminated with water or dirt (causes hard starting and surging).
- Avoid: Overfilling the tank; leave room for expansion.
- Do first: Confirm the exact fuel notes and safety rules in the 917378501 owner's manual.
Quick comparison: 87 vs 91 in a walk-behind mower
| Fuel choice | What you get | Best use case |
|---|---|---|
| 87 octane | Correct combustion for most mower engines | Everyday mowing, best value |
| 91 octane | No performance gain if the engine is not designed for it | Only if your manual specifically calls for it |
Why it matters
Using the right fuel helps your mower start easier, run smoother, and reduces carburetor and fuel-system problems. Most “won’t start” complaints trace back to stale fuel, dirty air flow, or neglected maintenance, not octane.
If your mower runs rough after refueling
Try these checks (safe, high-impact steps):
- Drain old fuel and refill with fresh 87.
- Check the air filter for clogging.
- Inspect and replace the spark plug at the start of the season or every 100 hours (the manual lists the exact type and gap).
- Keep the mower housing and engine area clear of grass and debris (a clogged engine runs hotter and shortens engine life).
- If the self-propelled wheels bind, clean debris from the wheel and dust cover area; the manual outlines the cleaning steps.
Helpful DIY resource
If you are also servicing the cutting system, follow how to sharpen a lawn mower blade for safe blade handling and better cut quality.
Last updated: February 2026
What model number is the Craftsman 917378501?
The model number for this Craftsman gas walk-behind lawn mower is 917.378501 (often written without the dot as 917378501). You can confirm the exact formatting and where to find the ID label in the 917378501 owner's manual.
Where to find the model number on the mower
Most Craftsman walk-behind mowers list the model number on a product ID label. Check these common spots:
- Rear of the deck near the discharge chute area
- Top of the deck near the engine mounting area
- Near the rear door or bagger opening
- On the handle support bracket area
- In the manual’s identification section
Why the dot matters (917.378501 vs 917378501)
Both formats refer to the same mower; the dot is a formatting style used in many manuals and parts diagrams.
| You might see it as | What it means | When it’s used |
|---|---|---|
| 917.378501 | Same model number | Owner’s manuals, diagrams |
| 917378501 | Same model number | Parts lookups, tags, listings |
Why it matters when ordering parts
Using the exact model number helps us match the correct blade, drive components, and hardware for your deck and drive system.
- Prevents ordering the wrong drive belt size
- Ensures the correct wheel and dust cover style
- Helps match the correct height adjuster parts
- Improves accuracy for handle and control cable parts
If you are replacing a common wear item, match by model first, then confirm by part ID. For example, the premium blade 532406706 is a model-matched blade option listed for Craftsman 917378501.
Last updated: February 2026
What year is Craftsman Model 917378501?
Craftsman model 917378501 is identified by its model number, not a built-in “year” code. For this mower, the most reliable way to confirm the manufacturing date is to use the product identification label details and the date guidance shown in the 917378501 owner's manual.
How to find the date information on your mower
Look for the product ID label (typically on the rear of the deck, near the engine, or on the handle support). Then record the key details below.
- Model number: 917378501
- Serial number (write it exactly as shown)
- Engine model/type and code (often on the engine shroud)
- Any date or “code” printed on the label
What to do with the numbers you find
Different Craftsman walk-behind mowers and engines use different date formats. Use this quick guide to narrow it down.
| Where you find the code | What it usually tells you | What to record |
|---|---|---|
| Mower product label | Mower identity and production run info | Model and serial number |
| Engine label/stamp | Engine build date code | Engine code and type |
| Manual parts pages | Confirms model family and assemblies | Model number and key assemblies |
Why it matters
Knowing the correct production date helps us match the right parts and diagrams for your exact build, especially for wear items like the blade, drive system, and hardware.
Common parts that vary by build
If you are ordering parts for 917378501, confirm fit by model and diagram before buying:
- Premium blade 532406706 (blade length and deck style must match)
- Lawn mower ground drive belt, 3/8 x 33-9/16-in 532169778 (drive systems can differ)
- Cable.mzr.60 532183567 (control cable length and end fittings matter)
Last updated: February 2026
