Craftsman 917378403 gas walk-behind lawn mower Parts

For Craftsman model 917378403, the serial number is printed on a decal on the rear of the lawn mower housing; that decal tells you the mower’s identity, but the serial itself does not use one universal date format. We use the serial number to identify the correct parts and manual, then match it to the manufacturing date information for your unit.

Where to find the serial number on model 917378403

Look for the model and serial number decal in this location:

• Rear of the lawn mower housing (back of the deck)
• On a decal, not stamped into the metal
• Near where you would record the serial number and purchase date in the documentation

For the exact decal location diagram and recording fields, use the 917378403 owner's manual.

How to estimate the build date from the serial number

Once you have the full serial number, use these practical checks:

• Look for a date code pattern at the beginning or end (common formats include YYMM, MMYY, or MMDDYY).
• Check for a week-year code (for example, a two-digit week followed by a two-digit year).
• Ignore spaces and dashes; write the serial as one continuous string before decoding.
• Compare to the mower’s feature set (deck size, drive type, handle style) to confirm you are reading the correct decal.

Quick decode guide (common patterns)

These are the most common serial date-code styles we see on walk-behind mowers; use them as a starting point.

What you see in the serial	Often means	Example result
YYMM...	Year, then month	2104 = April 2021
MMYY...	Month, then year	0421 = April 2021
MMDDYY...	Month, day, year	040521 = April 5, 2021

Why it matters

Knowing the mower’s age helps us match the correct Craftsman parts and specifications for maintenance items like blades, belts, and drive components, especially when designs change mid-series.

Last updated: January 2026

On the Craftsman gas walk-behind lawn mower model 917378403, the model number is typically printed on a sticker on the rear of the mower deck, near the lower handle mounting area. Use that number to match the correct parts list and diagrams in the 917378403 owner's manual.

Where to look on the mower

Check these common label locations on walk-behind mowers like model 917378403:

• Back of the deck (rear-facing side), between or near the lower handle mounts
• Rear door area (near the grass bag opening)
• Side of the deck near the wheel height adjuster
• Under the handle crossbar (less common)

What the label usually shows

Most Craftsman mower ID stickers include more than just the model number.

Label item	What it’s used for
Model number	Ensures you get the right diagrams and parts
Product number	Helps narrow down exact configuration
Serial number	Helps identify production run details

Tips if the sticker is dirty or worn

If the sticker is hard to read, these steps usually work:

• Wipe the area with a damp rag and mild detergent; let it dry
• Use a flashlight at an angle to make faint printing easier to see
• Take a close-up photo and zoom in
• If only part of the number is readable, compare it to the format shown in the 917378403 owner's manual

Why it matters

Craftsman walk-behind mowers can look similar across multiple model numbers, but parts like the drive system, control cable, and blade can differ. Using the exact model number helps us match the correct components the first time.

Last updated: January 2026

The model number is 917.378403 (often written without the dot as 917378403) for this Craftsman gas walk-behind lawn mower. You’ll see this exact model number printed on the mower’s model/serial tag and throughout the parts diagrams in the 917378403 owner's manual.

Where to find the model number on the mower

We recommend checking the model/serial tag first, then matching it to the manual’s parts breakdown.

• Look for a model/serial label on the mower deck (typically near the rear or side of the deck)
• Clean off grass and debris so the full number is readable
• Match the full model number exactly (including any dots)
• Use the model number when ordering parts like a blade, drive belt, or control cable

Why you might see it written two ways

Both formats refer to the same mower; the dot is a formatting style used in some manuals and labels.

Format you see	What it means	What to use when searching parts
917.378403	Manual/label formatting	917378403 (works best)
917378403	Search and parts lookup formatting	917378403

Why it matters

Using the exact Craftsman model number ensures you get the correct diagrams and compatible parts for your mower’s drive system, handle/control components, and cutting deck hardware.

Last updated: January 2026