Craftsman 917377971 21" 6.75-hp rotary lawn mower Parts

On the Craftsman walk-behind mower model 917377971, the model and serial number are typically printed on a decal attached to the rear of the mower housing. We recommend matching the full model number exactly before ordering parts to ensure proper fit. See the 917377971 owner's manual for the label location and recording space.

Where to look on model 917377971

Check these common spots on this specific mower:

• Rear of the mower housing (most common for this model)
• Near the rear discharge door area
• On the deck housing surface where debris is less likely to scrape it off
• If the decal is worn, look for an imprint outline or adhesive residue where it used to be

What to write down (and why)

Record both numbers from the decal:

• Model number (example format: 917.377971)
• Serial number (unique to your mower)
• Date of purchase (helpful for maintenance tracking)

Why it matters

The model number narrows parts to the correct Craftsman design version. The serial number can help confirm production variations when a part changed mid-run.

Quick check: model number vs. serial number

Item	What it identifies	Used for
Model number	The mower design family	Choosing compatible parts and diagrams
Serial number	Your exact unit	Confirming production-specific variations

If the decal is missing or unreadable

If you cannot read the decal on your 917377971 mower, use these practical options:

• Compare your mower’s features (drive control, discharge style, handle style) to the diagrams for model 917377971
• Check any original paperwork or the owner’s manual cover page if you still have it
• If you are replacing a wheel-related item, confirm the wheel and hardware style before ordering (for example, a dust cover like husqvarna lawn mower wheel dust cover 581840401 must match your wheel setup)

Last updated: January 2026

On the Craftsman 917377971 21-inch 6.75-hp walk-behind mower, the most common problems we see are starting issues (fuel, spark, air), loss of power from restricted airflow or heavy buildup under the deck, and self-propel drive problems from belt or drive hardware wear. For model-specific maintenance intervals and troubleshooting steps, use the 917377971 owner’s manual.

Most common issues (and what they usually point to)

• Won’t start or starts then dies: stale fuel, dirty air filter, disconnected spark plug wire, weak battery (electric start models), or carburetor/fuel contamination.
• Loss of power or bogging down: clogged air filter, mowing too low in heavy grass, or grass buildup under the mower housing.
• Poor cut or uneven cut: dull/bent blade, low blade speed, or deck packed with wet clippings.
• Excessive vibration: loose blade hardware, damaged blade, or (less commonly) a bent crankshaft.
• Self-propel not pulling: worn or off-track drive belt, worn drive cable, or debris in the drive pinions.

Quick checks we recommend first (fast, high-impact)

1. Use fresh regular unleaded fuel and drain old fuel if it has been sitting.
2. Check the air filter; replace if dirty (a restricted filter can cause hard starting and power loss).
3. Inspect the blade area safely (spark plug wire disconnected); remove packed grass from under the deck.
4. Confirm blade hardware is tight and the blade is not bent.
5. If self-propel slips, inspect the belt and drive components; the lawn mower ground drive belt 532166060 is a common wear item on this model.

Symptom-to-cause cheat sheet

Symptom	Most likely cause	Typical fix
Won’t start	fuel/air/spark issue	fresh fuel, clean/replace filter, new spark plug
Cuts poorly	dull/bent blade	sharpen/replace blade, clean deck
Vibrates	loose/damaged blade	tighten or replace blade/hardware
Hard to push	cutting too low, bag full	raise height, empty bag
No self-propel	belt/cable/pinions	inspect belt, cable, clean pinions

Why it matters

Catching these problems early helps prevent bigger failures (like overheating from deck buildup or damage from running with a loose blade). It also keeps cut quality consistent and reduces strain on the engine and drive system.

Last updated: January 2026

On the Craftsman 917377971 21-inch 6.75-hp walk-behind mower, the most common repairs are usually basic maintenance fixes: fuel-related no-start issues, air filter and spark plug service, blade and blade adapter problems, and self-propel drive issues such as a worn belt or drive components. See the 917377971 owner’s manual for the troubleshooting chart and maintenance schedule.

Most common repairs we see on this model

• Won’t start or hard starting: stale fuel, dirty air filter, disconnected spark plug wire, weak battery (electric start models)
• Loss of power: dirty air filter, grass buildup under the deck, cutting too low in heavy grass
• Poor cut or uneven cut: dull/bent blade, deck packed with clippings, mowing too fast
• Excessive vibration: loose blade bolt, damaged blade, damaged blade adapter
• Self-propel problems (loss of drive or hard to push): worn/broken belt, belt off pulley, debris in drive pinions

Quick checks before you buy parts

1. Fuel: Use fresh regular unleaded gas; if fuel is older than about 30 days, drain and refill.
2. Airflow: Inspect and replace the air filter if dirty.
3. Ignition: Confirm the spark plug wire is firmly connected; replace the spark plug if fouled.
4. Deck condition: Scrape grass buildup from the underside of the mower housing.
5. Drive system: If self-propel slips, inspect the belt and drive components.

Parts that commonly solve these problems

Symptom	Likely area	Example compatible part for this model
Vibration, blade won’t stay tight	Blade mounting	Lawn mower blade adapter 581547901
Poor cut, ragged grass tips	Cutting system	Husqvarna lawn mower mulching blade, 21-in 159267
Self-propel slips or won’t pull	Drive system	Lawn mower ground drive belt 532166060

Why it matters

Catching these issues early helps prevent bigger failures (like damaged crankshafts from severe blade impacts) and keeps your Craftsman mower cutting cleanly, starting reliably, and driving smoothly.

Last updated: January 2026

A gas walk-behind mower like Craftsman model 917377971 typically lasts 8 to 10 years with normal residential use and routine maintenance. Many units run longer if the engine oil is changed on schedule, the blade is kept sharp, and the deck is kept clean (see the 917377971 owner’s manual).

What affects lifespan the most

• Maintenance frequency: oil changes, air filter service, spark plug replacement
• Storage habits: dry storage, fuel stabilized or drained for off-season
• Operating conditions: dusty mowing, sandy soil, steep slopes, heavy wet grass
• Deck care: grass buildup under the housing increases heat and load
• Blade condition: dull or bent blades strain the engine and drive system

Quick “replace vs. repair” guide

If you see this	What it usually means	Typical next step
Starts hard, runs rough, smokes	Fuel, air, spark, or oil-related issue	Tune-up items first (oil, filter, plug)
Excessive vibration	Blade or blade adapter issue	Inspect blade and adapter; replace if damaged
Poor cut quality	Dull/worn blade or deck buildup	Clean deck; replace blade if needed
Drive problems (self-propel)	Belt/pulley/cable wear	Inspect belt and pulleys; replace worn parts

Maintenance milestones that help you reach 10+ years

We recommend following the schedule in the manual; these items have the biggest payoff:

• Change engine oil about every 25 hours of operation or each season
• Replace the air filter yearly (more often in dusty conditions)
• Replace the spark plug yearly and set the correct gap
• Keep the underside of the mower deck clean after use
• Keep the blade sharp; replace it when bent, cracked, or badly worn

Why it matters

A mower that is maintained to spec usually costs less per season to own, cuts more evenly, and is less likely to develop expensive secondary damage (like vibration-related wear in the crankshaft area).

Last updated: January 2026