Owner’s manual
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Should I use 87 or 91 gas for lawn mower?
For the Craftsman rotary lawn mower model 917377784, we use fresh regular unleaded 87-octane gas for normal operation; higher octane (like 91) does not add power or improve reliability in this mower. For fuel handling and storage steps, follow the owner's manual.
What to use (and what to avoid)
- Use: Fresh, clean 87 octane unleaded gasoline.
- Avoid: Old or stale gas; it causes hard starting and rough running.
- Avoid: Fuel that has absorbed moisture or separated during storage.
- Do not add: Engine or carburetor cleaner products to the fuel tank (this can cause permanent damage).
- For storage: If the mower will sit 30 days or longer, empty the fuel system before storage.
Why 91 octane usually is not better
Octane is mainly about resistance to knock, not “strength.” Most walk-behind mower engines are designed to run correctly on regular fuel, so moving from 87 to 91 typically provides no benefit.
Quick comparison
| Fuel choice | Best use case | What you’ll notice |
|---|---|---|
| 87 octane (regular) | Everyday mowing | Normal starting and performance |
| 91 octane (premium) | Not needed for this mower | Usually no change in power or starting |
Storage tips that prevent fuel problems
The manual’s storage guidance is the biggest reliability win:
- If storing 30+ days, run the engine until the tank, fuel lines, and carburetor are empty.
- Use fresh fuel next season.
- Replace rusty gas cans; rust and dirt contaminate fuel.
- Never store the mower indoors with gasoline in the tank where fumes could reach a flame or spark.
Why it matters
Using the right fuel and storing it correctly prevents carburetor varnish, moisture-related corrosion, and “won’t start” complaints, which are the most common fuel-related mower issues.
Last updated: January 2026
What model number is the Craftsman 917377784?
The model number for this Craftsman rotary lawn mower is 917.377784 (often written without the dot as 917377784). You’ll see this exact model number printed in the product documentation and used to match the correct walk-behind mower parts for your machine.
Where to confirm the model number on the mower
Check these common ID locations first:
- The model tag/label on the mower deck (top or rear area)
- Near the rear discharge door or bagger mounting area
- On the handle support/frame area
- In the documentation for the mower
For the official listing and diagrams, use the 917377784 owner's manual.
Why the dot matters (917.377784 vs 917377784)
Both formats refer to the same mower; the dot is a formatting style used on some labels and manuals.
| You see this | Use it for | What it means |
|---|---|---|
| 917.377784 | Manual/ID label lookups | Same model number with punctuation |
| 917377784 | Parts searches and ordering | Same model number without punctuation |
Why it matters when ordering parts
Using the exact model number helps us match the right diagrams and hardware for your Craftsman walk-behind mower, especially for drive and deck-related items.
- Prevents ordering the wrong handle, wheel, or drive parts
- Ensures correct fit for fasteners and small hardware
- Helps match the correct gearcase and drive control components
- Speeds up troubleshooting when the mower will not move or will not start
If you’re working on the drive system, a commonly referenced component on this model is the lawn mower drive cable 583180101 (used with the drive control assembly).
Last updated: January 2026
Where is Craftsman's model number?
On the Craftsman rotary lawn mower model 917377784, the mower’s model number is printed in the product documentation and is also typically found on a model and serial number label on the mower deck (often near the rear discharge area or rear wheel height adjuster). For exact label location details, use the 917377784 owner's manual.
Where to look on the mower
Check these common spots on walk-behind mowers first:
- Top of the mower deck near the rear of the engine
- Rear of the deck near the discharge chute opening
- Side of the deck near a rear wheel height adjuster
- Near the handle mounting brackets on the deck
- On a label that includes both model and serial numbers
Mower model number vs. engine model number
This mower has two different identifiers that people often mix up:
| What you are identifying | What it’s used for | Where you’ll usually find it |
|---|---|---|
| Mower model number (917377784) | Ordering Craftsman mower parts (wheels, drive parts, handle parts) | Label on the mower deck |
| Engine model number (143.046702) | Ordering engine parts (carburetor, recoil starter, ignition parts) | Stamped/printed on the engine shroud or engine ID tag |
The 917377784 owner's manual lists the mower as model 917.377784 and also shows the engine as model 143.046702, which helps confirm you are using the right parts breakdown.
Why it matters
Using the correct model number prevents ordering the wrong drive cable, wheel hardware, or deck components. Even small differences in a Craftsman walk-behind mower series can change the blade adapter, handle parts, and self-propelled drive system.
Last updated: January 2026
