Owner’s manual
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Should I use 87 or 89 gas for lawn mower?
Use 87-octane regular unleaded gasoline in your Craftsman 917377810 gas walk-behind mower; higher octane like 89 is not needed for normal operation. For best starting and to prevent fuel-system issues, use fresh fuel and follow the fuel guidance in the owner's manual.
What fuel to use (and what to avoid)
- Use fresh, clean, regular unleaded gas with a minimum of 87 octane.
- Do not mix oil with gasoline.
- Avoid old fuel; buy only what you can use in about 30 days.
- Avoid alcohol-blended fuels when possible; ethanol blends can attract moisture during storage.
- If the mower will sit 30 days or longer, run the fuel system dry before storage.
87 vs 89: what changes?
In a mower engine like this, octane is mainly about knock resistance, not power. If the engine is designed for regular fuel, moving from 87 to 89 typically does not improve performance.
| Fuel choice | OK to use? | What to expect |
|---|---|---|
| 87 octane (regular) | Yes (recommended) | Normal power and starting |
| 89 octane (mid-grade) | Yes | Usually no noticeable benefit |
| Old/stale gas | No | Hard starting, rough running |
Why it matters
Fuel quality is one of the biggest causes of “won’t start” and “runs poorly” complaints on walk-behind mowers. Fresh 87-octane fuel helps protect the carburetor and fuel lines, especially after storage.
If it still runs rough after fresh gas
- Check the oil level (too much oil can cause running issues).
- Inspect and service the air filter.
- Check the spark plug and plug wire connection.
- Clean built-up grass and debris from the mower deck and engine area.
Last updated: February 2026
What are the common problems with Craftsman lawn mowers?
Common problems on the Craftsman 917377810 gas walk-behind lawn mower include no-start conditions (stale fuel, dirty air filter, bad spark plug, disconnected plug wire), loss of power from airflow or fuel issues, and poor cutting from a worn or loose blade or grass buildup under the deck. For model-specific checks and adjustments, use the owner's manual.
Most common symptoms and what they usually mean
- Engine will not start: dirty air filter, out of fuel, stale fuel, water in fuel, bad spark plug, control bar not held down
- Loss of power: heavy grass load, cutting too much at once, dirty air filter, deck packed with clippings, oil level too high
- Poor or uneven cut: worn/bent blade, wheel height mismatch, debris buildup under the mower
- Vibration or rattling: loose blade bolt, damaged blade, or a failing blade adapter
- Self-propelled issues (won’t move or slips): worn or stretched ground drive belt, idler pulley wear, linkage out of adjustment
Quick troubleshooting checklist (start here)
- Drain old gas and refill with fresh fuel if the mower sat more than a month.
- Check the air filter; clean or replace if dirty.
- Verify the spark plug wire is firmly connected; replace the spark plug if fouled.
- Hold the control bar fully against the handle while starting.
- Tip the mower only as directed in the owner's manual to avoid oil or fuel flooding.
Parts that commonly solve these problems
If you find wear or damage during inspection, these model-matched parts are common fixes:
| Problem you see | Likely part involved | Example part for this model |
|---|---|---|
| Blade loose, mower shakes, poor cut | Blade adapter | Lawn mower blade adapter 581547901 |
| Poor cut quality | Mulching blade | Husqvarna lawn mower mulching blade, 21-in 159267 |
| Self-propel won’t drive | Ground drive belt | Lawn mower ground drive belt 532166060 |
Why it matters
Most “big” mower failures start as small maintenance issues. Fresh fuel, clean airflow, correct oil level, and a clean deck prevent hard starting, power loss, and premature wear on the blade, belt, and pulleys.
Last updated: February 2026
How do I find the model number on my 917377810?
Your Craftsman walk-behind mower’s model number is printed on the mower’s model tag; for this unit it appears as 917.377810 (often shown with a dot). Use that exact number when looking up parts, diagrams, and specifications in the 917377810 owner's manual.
Where to look on the mower
On most Craftsman walk-behind mowers, the model tag is on the mower deck (the metal housing around the blade) or near the rear of the deck behind the engine.
- Check the top of the deck near the engine mounting area
- Check the rear deck area near the bagger opening
- Look for a sticker or metal plate labeled Model No.
- Wipe off grass and dirt; the print is often faint
- Write the number down exactly, including any dots or dashes
What the model number should look like
The manual identifies this mower as Model No. 917.377810. You may see it formatted slightly differently on the tag.
| Where you see it | Example | What to enter for parts lookup |
|---|---|---|
| Model tag on mower | 917.377810 | 917377810 |
| Owner’s manual cover | 917.377810 | 917377810 |
Why it matters
Craftsman model numbers control the exact parts breakdown. Even small differences can change items like the drive system, blade adapter, or ground drive belt. Once you confirm the model, you can match parts precisely, such as the lawn mower ground drive belt 532166060 or the husqvarna lawn mower mulching blade, 21-in 159267.
Last updated: March 2026
