Owner’s manual
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Should I use 87 or 89 gas for lawn mower?
For the Craftsman 917388391 21-inch 6-hp walk-behind mower, we use fresh, clean regular unleaded gasoline (87 octane) in normal conditions; 89 octane is fine but usually unnecessary. The bigger priority is safe fueling and keeping fuel fresh, as outlined in the 917388391 owner's manual.
What to use (and what to avoid)
- Use: fresh regular unleaded 87 octane from a busy station
- Okay to use: 89 octane (no harm, just typically no added benefit)
- Avoid: old gas (more than about 30 days without stabilizer)
- Avoid: fuel contaminated with water or dirt
- Avoid: overfilling the tank; leave room for expansion
Fueling safety steps we follow
The manual emphasizes safe fueling practices to prevent fire and injury.
- Shut the engine off and let it cool for several minutes before fueling
- Fuel outdoors (not indoors or in an enclosed shed)
- Wipe up spilled gasoline before starting
- Keep hands and feet away from moving parts; disconnect the spark plug wire before service
Quick comparison: 87 vs 89 for this mower
| Fuel choice | Will it run? | When it makes sense |
|---|---|---|
| 87 octane (regular) | Yes | Everyday mowing, normal loads |
| 89 octane (midgrade) | Yes | If it is the only fresh fuel available |
Why it matters
Using the right fuel helps your air-cooled engine start easier, run cleaner, and avoid carburetor issues caused by stale gas. Fresh fuel and good maintenance usually make a bigger difference than stepping up from 87 to 89.
If you are doing a seasonal tune-up, pairing fresh fuel with basic maintenance parts can help; for example, a briggs & statton tune-up kit 5140B is commonly used for routine service items.
Last updated: February 2026
What are the common problems with Craftsman lawn mowers?
On the Craftsman 917388391 21" 6-hp multi-cut rotary lawn mower, the most common problems are no-start or hard-start conditions (fuel, spark, air), loss of power from restricted airflow or heavy cutting, and poor cut or vibration caused by blade or blade-mounting issues. Use the 917388391 owner's manual troubleshooting chart to match symptoms to fixes.
Most common symptoms and what usually causes them
- Won't start / hard to start: stale fuel, dirty air filter, fouled spark plug, or improper priming (over-priming can flood the engine)
- Loss of power: dirty air filter, grass buildup under the deck, cutting too much grass, walking speed too fast
- Poor cut or uneven cut: wheel height set unevenly, worn/bent blade, deck packed with clippings
- Excessive vibration: worn/bent blade, loose blade hardware, or (more serious) bent crankshaft after an impact
- Starter rope hard to pull: blade dragging in grass, blade adapter damage, or crankshaft issues
Quick checks we recommend (fastest wins first)
- Fuel: Drain old gas and refill with fresh gasoline.
- Airflow: Clean or replace the air filter; keep the top of the engine clear of clippings.
- Spark: Inspect and replace the spark plug if fouled.
- Deck condition: Tip the mower safely and clear packed grass from under the housing.
- Cut settings: Raise the cutting height in tall grass; overlap passes and slow down in heavy cutting.
Parts that commonly get involved
If you see vibration, poor cutting, or the engine struggles after hitting something, inspect the blade mounting stack-up.
| Symptom | Part to inspect | What to look for |
|---|---|---|
| Vibration or uneven cut | Lawn mower blade adapter 581547901 | Cracks, wobble, stripped drive features |
| Side discharge issues | Discharge guard 589482402 | Binding, damage, missing hardware |
| Control must be held to run | Lawn mower control bar 532131696 | Bent bar, not returning smoothly |
Why it matters
Most “common problems” on a gas walk-behind mower trace back to basic maintenance (fuel, air, spark) or cutting conditions. Fixing those first prevents repeat no-start issues, reduces engine strain, and helps avoid damage to the blade adapter and crankshaft.
Last updated: February 2026
What model Craftsman do I have?
If you have the Craftsman walk-behind mower shown on this page, your model number is 917388391. On most Craftsman push mowers, the model tag is on the mower deck or frame; match the full model number on the tag to the number shown in the 917388391 owner's manual.
Where to find the model number on a Craftsman push mower
Look for a sticker or metal tag in these common spots:
- On top of the mower deck near the engine
- On the rear of the deck near the bagger opening
- On the frame by the handle mounting brackets
- Near the height adjuster area by a rear wheel
- Under the grass bag or behind the discharge guard area
What to write down (so you get the right parts)
For Craftsman model 917388391, we recommend recording these items from the tag:
- Model number (example: 917388391)
- Product number (if listed)
- Serial number (helps confirm production run)
- Engine model (this mower uses a Briggs & Stratton engine; the manual lists 12H802-2675-B1)
Quick ID checklist
| Item | What it does | Example for this mower |
|---|---|---|
| Mower model number | Matches the correct parts diagrams | 917388391 |
| Engine model number | Matches engine parts like spark plug, carb parts | 12H802-2675-B1 |
Why it matters
Craftsman mowers can look similar across years, but parts like the blade adapter, control cable, and handle hardware can vary by model and engine family. Using the exact model number helps us point you to the correct Craftsman walk-behind mower parts the first time.
Last updated: February 2026
What model number is the Craftsman 917388391 engine?
The Craftsman 917388391 walk-behind mower uses a Briggs & Stratton 4-cycle engine with model number 12H802-2675-B1. You can confirm the engine identification and view the engine breakdown in the 917388391 owner’s manual.
Where to find the engine model number on the mower
On most Craftsman walk-behind mowers, the engine model number is stamped on the engine itself (not on the mower deck tag). Check these common spots:
- Blower housing (recoil starter shroud) near the pull cord
- Valve cover area on the side of the engine
- Muffler heat shield area
- A stamped metal pad near the spark plug
- A label near the primer bulb (if equipped)
Why the engine model number matters
The mower model number (917388391) identifies the deck and handle parts; the engine model number (12H802-2675-B1) identifies engine-specific parts like the spark plug, carburetor kit, gasket sets, and ignition components. Using the correct engine model prevents ordering the wrong tune-up or carburetor parts.
Quick ID reference
| Item | What it identifies | Example for this mower |
|---|---|---|
| Mower model number | Deck, wheels, handle, bagging and mulching parts | 917388391 |
| Engine model number | Engine internal and external engine parts | 12H802-2675-B1 |
Related mower parts you might replace during service
If you are doing a seasonal tune-up or fixing a starting issue, these common mower (non-engine) parts are often involved:
- Briggs & statton tune-up kit 5140B (engine maintenance kit)
- Husqvarna lawn mower zone control cable 532162778 (operator presence/stop cable)
- Lawn mower control bar 532131696 (handle control bar)
- Rope guide 586122501 (starter rope routing)
- Grass bag 532410666 (bagging performance)
Last updated: February 2026
What model number is the Craftsman 917388391?
The model number for this Craftsman walk-behind mower is 917.388391 (often written without the dot as 917388391). You can confirm it on the model tag and in the 917388391 owner's manual.
Where to find the model number on the mower
We recommend checking these common locations on a 21-inch Craftsman rotary mower:
- On the rear of the mower deck near the discharge opening
- On the deck housing near the engine mounting area
- Near the handle mounting brackets
- On a sticker or metal plate that also lists safety and emissions information
Model number vs. engine model number (common mix-up)
This mower has its own model number, and the Briggs & Stratton engine has a separate engine model number. Use the mower model number for chassis parts (handle, wheels, guards); use the engine model number for engine-specific parts.
| What you are identifying | Example for this mower | Use it to find |
|---|---|---|
| Mower model number | 917.388391 (917388391) | Craftsman deck and handle parts, wheels, guards, bagging parts |
| Engine model number | 12H802-2675-B1 | Briggs & Stratton engine parts like spark plug, carburetor items |
Why it matters
Using the correct model number helps us match the exact parts diagram and hardware for your Craftsman 917388391, so you get the right fit for items like the control bar, discharge guard, and blade mounting components.
Last updated: February 2026
What size engine is in the Craftsman 917388391?
The Craftsman model 917388391 (21" 6-hp multi-cut rotary lawn mower) uses a Briggs & Stratton 4-cycle engine, model 12H802-2675-B1. This engine family is commonly referred to as a 6 HP-class walk-behind mower engine; use the engine model number for tune-up and engine parts matching.
Where to confirm the engine identification
We recommend verifying the engine model and type directly on the engine label and in the 917388391 owner’s manual. This avoids ordering the wrong ignition, carburetor, or starter parts.
- Look for the stamped/printed engine model on the blower housing or valve cover area
- Match the engine model to the manual’s engine breakdown pages
- Use the engine model when shopping for spark plug, air filter, and carburetor parts
- If the label is dirty, wipe it and use a flashlight to read the numbers
What “engine size” usually means (and what to use instead)
On walk-behind mowers, “engine size” can mean horsepower class, displacement (cc), or the engine model. For the 917388391, the most reliable identifier is the Briggs & Stratton 12H802-2675-B1 model.
| If you need… | Use this identifier | Why it helps |
|---|---|---|
| Engine parts lookup | Briggs & Stratton 12H802-2675-B1 | Matches the correct engine breakdown |
| Mower parts lookup | Craftsman 917388391 | Matches deck, handle, wheels, and controls |
| Routine maintenance | 6 HP-class, 4-cycle | Helps choose common service items |
Why it matters
Using the correct engine model prevents common fit issues, especially with tune-up items and fuel system parts. For example, a tune-up kit is typically selected by engine model, not by mower deck size.
If you are also troubleshooting a no-start or hard-start condition, checking the control cable and handle controls can help; the zone control cable 532162778 is one of the key safety/stop controls on this mower.
Last updated: February 2026
What year is a Craftsman 917388391 riding mower?
The Craftsman 917388391 is not a riding mower; it is a 6.0 HP, 21-inch multi-cut rotary walk-behind lawn mower. The model number identifies the mower and parts, but it does not reliably translate to a single “model year”; we use the purchase date and the model/serial label for dating.
Confirm the product type first
This model is documented as a walk-behind rotary mower in the 917388391 owner's manual. That matters because “917” model numbers are used across multiple Craftsman product types, including riders and walk-behinds.
- Walk-behind mower: 21-inch deck, push/self-propel style
- Riding mower: seat, steering, larger deck (typically 30 inches and up)
- Parts and diagrams differ by product type even when the prefix looks similar
How to find the year (best method)
For Craftsman outdoor power equipment, the most accurate way to determine the year is to use the model/serial label and your proof of purchase.
- Check the mower’s model/serial label (commonly on the rear of the deck, near the handle brackets, or on the housing)
- Record the full model number and serial number exactly
- Use the original receipt to confirm the purchase date (often the simplest “year” reference)
- If the engine has its own model/type/code label, record that too (engine date codes can narrow the timeframe)
What we can say from the manual
The manual confirms the exact model identity and configuration, which is what you need to match parts and diagrams.
| Item | What it tells you | What it does not tell you |
|---|---|---|
| Model number (917388391) | Correct parts and assemblies | Exact manufacturing year |
| Owner’s manual | Operation, maintenance, repair parts lists | Exact build date |
| Purchase date | Practical “year” for warranty and age | Exact factory date |
Why it matters
The “year” is less important than the exact model number when ordering parts like a control cable, blade adapter, or handle hardware. For example, the parts list for this model includes items such as the lawn mower zone control cable 532162778 and lawn mower blade adapter 581547901, which must match your mower’s configuration.
Last updated: February 2026
Where is Craftsman's model number?
On your Craftsman walk-behind mower, the model number is on the mower’s ID label (not on the engine). For this mower, the owner’s manual lists the model as 917.388391; use that number when ordering non-engine parts. See the 917388391 owner's manual for the exact identification details.
Where to look on the mower
We typically find the model/serial label in one of these spots on a 21-inch Craftsman walk-behind mower:
- On the rear of the mower deck near the bagger opening
- On the side of the deck near a rear wheel height adjuster
- On the handle bracket area where the handle bolts to the deck
- Under the rear discharge door or near the discharge chute area
What number to use (mower vs. engine)
Your mower has two different “model numbers,” and they are used for different parts.
| What you’re identifying | Example for this mower | Used to order | Where it’s found |
|---|---|---|---|
| Mower model number | 917.388391 | Deck, wheels, handle, bag, blade adapter, cables | Mower ID label |
| Engine model number | 12H802-2675-B1 (Briggs & Stratton) | Engine parts (carburetor, ignition, muffler, etc.) | Engine shroud/blower housing |
Why it matters
Using the mower model number (917388391) keeps you matched to the correct walk-behind mower parts diagrams and hardware. For example, common mower-side parts include the lawn mower control bar 532131696 and the lawn mower blade adapter 581547901.
Quick tips to read the label correctly
- Write the model number exactly as shown (include dots if present)
- Record the serial number too (helps with production variations)
- Clean the label area first; grass and oil can hide digits
- Use the mower model for chassis parts; use the engine model for engine parts
Last updated: February 2026
