Craftsman 917378780 gas walk-behind lawn mower Parts

The most common issues we see with the Craftsman 917378780 gas walk-behind lawn mower are drive problems (won’t self-propel or slips), uneven cutting, and hard starting or stalling. These usually trace back to the ground drive belt and wheel/height hardware, plus basic fuel and blade-deck maintenance. For model-specific adjustments and diagrams, use the 917378780 owner's manual.

Common symptoms and what typically causes them

• Self-propel quits or slips: worn or stretched drive belt, loose drive cover, worn drive wheel, or a drive pinion gear issue.
• Mower pulls to one side: uneven wheel height settings, worn drive wheel tread, or a bent/debris-packed deck.
• Uneven cut or scalping: height adjuster not holding position, missing retaining hardware, or deck buildup.
• Hard starting, surging, or stalling: stale fuel, dirty air filter, fouled spark plug, or carburetor varnish.
• Excess vibration: damaged blade, loose fasteners, or debris wrapped around the blade adapter area.

Quick checks we recommend first (fast, no parts)

• Confirm fresh fuel and the correct oil level.
• Clean grass buildup under the deck (disconnect the spark plug wire first).
• Inspect the blade for bends, cracks, and tight mounting.
• Verify both sides are set to the same cutting height.
• Check the drive engagement cable feel; it should be smooth and return fully.

Parts that commonly fix drive and height problems

If the mower runs but won’t move well, these are frequent wear items for this model:

Symptom	Likely wear item	Example part on this model
Slips, weak drive	Ground drive belt	Lawn mower ground drive belt, 3/8 x 32-1/2-in 532175436
Poor traction or uneven pull	Drive wheel	Husqvarna lawn mower drive wheel, 8 x 2-in 532180775
Height won’t stay set	Height adjuster hardware	Husqvarna lawn mower height adjuster knob 532701037

Why it matters

Drive and height components wear gradually; fixing them early restores safe control on slopes, improves cut quality, and reduces strain on the transmission and deck hardware.

Last updated: March 2026

The model number is 917.378780 for this Craftsman gas walk-behind lawn mower; it is commonly written without the dot as 917378780. You can confirm the exact model format and view the illustrated parts breakdown in the 917378780 owner's manual.

Where to find the model number on the mower

We use the model number to match the correct parts (like the drive belt, wheels, and control cable) to your exact mower configuration.

• Check the model tag/label on the mower deck near the rear discharge area
• Look near the handle mounting brackets on the deck
• Inspect around the engine mounting area (on top of the deck)
• Wipe off grass and oil residue so the full number is readable
• Write it down exactly as shown, including any dots or spaces

Why the dot matters (917.378780 vs 917378780)

Both formats refer to the same mower; the manual lists it with a dot, while parts listings often omit punctuation.

You see it as	What it means	Use it for
917.378780	Manual/label formatting	Verifying the exact model on the ID tag
917378780	Parts lookup formatting	Searching parts and diagrams

Why it matters for parts and repairs

Using the correct model number prevents ordering the wrong drive system or wheel hardware, especially on self-propelled mowers where belt length and wheel components must match.

If you are troubleshooting drive issues, the manual parts section for model 917.378780 also references common drive components such as the lawn mower ground drive belt, 3/8 x 32-1/2-in 532175436 and related wheel/drive hardware.

Last updated: February 2026

Craftsman model 917.378780 is a specific rotary walk-behind mower model number, but Craftsman model numbers do not reliably map to a single public “model year” the way cars do. The most accurate way to date your mower is to use the identification information and parts breakdown in the 917378780 owner's manual and then match the engine’s date code.

How to find the build date on your mower

Use these checks in order; they work for most Craftsman walk-behind mowers:

• Check the mower deck tag (often on the rear of the deck or near the handle mounts) for a serial/date code.
• Check the engine label (Briggs & Stratton, Honda, etc.) for a model-type-code or date code; this is usually the fastest way to pinpoint the year.
• Compare key assemblies in the manual diagrams (handle, drive system, gear case) to confirm you are working from the correct model family.
• If the mower has self-propel drive issues, confirm the drive system parts list matches what’s installed (belt, wheels, control cable).

What we can say for this exact model

Your documentation identifies it as Craftsman rotary lawn mower model 917.378780 and includes detailed parts breakdowns for the drive and handle assemblies. That confirms the model identity, but it does not publish a single “made in year X” statement.

Model identifiers shown in the manual

Item in documentation	What it tells you	Why it helps
Model number 917.378780	Exact mower model	Confirms you have the right parts diagrams
Gear case assembly listing	Drive system design	Helps match the correct self-propel components
Handle/control listings	Control layout	Helps confirm configuration across revisions

Why it matters

Getting the year right helps most with engine parts (spark plug, carburetor, air filter) because those are tied to the engine’s model and date code, not just the mower’s 917-number. For mower-deck and drive parts, the 917.378780 parts list is typically the best match.

Related parts customers often replace on this model

• Lawn mower ground drive belt, 3/8 x 32-1/2-in 532175436 (self-propel drive belt)
• Condrol.driv 583134601 (drive control assembly)
• Husqvarna lawn mower drive wheel, 8 x 2-in 532180775 (drive wheel)

Last updated: February 2026