Craftsman 917378890 lawn mower Parts

On the Craftsman walk-behind mower model 917378890, the model number is printed on the mower’s identification label and is also shown on the cover of the 917378890 owner's manual. For this unit, the manual lists it as 917.378890 (same model, different punctuation).

Where to look on the mower

Check these common spots first (labels can be dirty or grass-stained):

• Rear of the mower deck, near the discharge opening
• Top of the deck near the engine mounting area
• Near the height adjuster area by a rear wheel
• On the handle support/bracket area
• Under the grass bag door area (rear discharge models)

Model number vs. engine numbers (important)

Many owners find an engine ID and assume it is the mower model. On walk-behind mowers, the mower model number and the engine model/type/code are different.

What you found	What it identifies	When you need it
Mower model number: 917378890 (or 917.378890)	The Craftsman mower and its parts diagrams	Ordering deck, wheel, drive, and handle parts
Engine model/type/code (stamped on engine)	The engine manufacturer and engine parts	Ordering carburetor, ignition, recoil starter, and engine gaskets

Tips to read the label successfully

• Clean the area with a damp rag and mild detergent; avoid pressure washing labels.
• Use a flashlight at a low angle to make faint printing easier to see.
• Write down the full number exactly; include all digits.

Why it matters

Using the correct model number ensures we match the right parts list for your mower’s drive system, wheels, handle hardware, and cutting deck components. It also prevents ordering look-alike parts that do not fit.

Last updated: January 2026

For Craftsman walk-behind mower model 917378890, the serial number is primarily used to identify the unit for service and parts; the most reliable way to confirm the manufacturing date is to match your serial number format and location shown in the 917378890 owner's manual.

Where to find the serial number on this mower

The manual specifies that the model and serial numbers are on a decal on the rear of the lawn mower housing. Use that decal information when you’re doing a serial number lookup.

• Look on the rear of the mower deck (housing) for the decal
• Record the model number (917378890) and the serial number exactly as printed
• Also record your date of purchase (the manual provides a space for it)
• Clean grass and dirt off the housing so the decal is readable

How “serial number to year” lookups usually work (what to check)

Craftsman serial number formats vary by manufacturer and era, so the “month-day-year” pattern you may see online is not universal. Use these checks to avoid a wrong year:

• Count the digits and note any letters or dashes
• Look for a separate date code on the engine (often different from the mower serial)
• Compare the serial format to the identification section in the 917378890 owner's manual
• Use the model number to ensure you’re referencing walk-behind mower information (not riding mower rules)

Quick comparison: mower serial vs. engine date code

Identifier	Where you’ll see it	What it’s best for
Mower model/serial decal	Rear of mower housing	Correct parts lookup and unit identification
Engine date code	Stamped/printed on engine	Engine build date reference

Why it matters

Getting the year right helps you avoid ordering the wrong Craftsman parts (especially drive system and wheel components) and speeds up troubleshooting when you reference diagrams and specs.

Last updated: January 2026

For the Craftsman lawn mower model 917378890, use fresh, clean regular unleaded gasoline (87 octane) for normal operation. Higher octane (like 91) does not add power in a typical small mower engine; fuel freshness and cleanliness matter more for easy starting and smooth running. See the fuel and storage guidance in the 917378890 owner's manual.

What to use (and what to avoid)

• Use 87 octane regular unleaded from a busy station (fresher fuel).
• Use fresh fuel; stale gas is a common no-start cause.
• Avoid storing gas from one season to the next.
• Keep dirt and rust out of the fuel can; contamination leads to running problems.
• If you store fuel, use a stabilizer and follow the manual’s storage steps.

Quick comparison: 87 vs 91 for a walk-behind mower

Fuel choice	Best use case	What you gain	Common downside
87 octane (regular)	Everyday mowing	Correct for most mower engines	None when fuel is fresh
91 octane (premium)	Not needed for normal mowing	No meaningful performance benefit	Higher cost; still goes stale

If your mower is hard to start or runs rough

Stale or contaminated fuel is more likely than octane to be the issue. We recommend these checks:

• Drain old fuel and refill with fresh, clean gasoline.
• Check the air filter and replace if dirty.
• Inspect the spark plug and replace if worn.
• Make sure the spark plug wire is firmly connected.
• Clean built-up grass and debris so the engine runs cooler.

Why it matters

Using the right fuel is mostly about preventing stale-gas and contamination problems that cause hard starting, surging, and poor performance. The manual also warns against storing gasoline from one season to the next and notes that rust or dirt in the gas can cause problems.

Last updated: January 2026