Owner’s manual
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What kind of engine does a Craftsman riding lawn mower have?
For Craftsman model 917255919, the tractor uses an 18 HP twin-cylinder engine (a GT 18 twin-garden tractor configuration). This twin-cylinder setup is designed for cool-running performance and strong power for mowing and other yard tasks; see the 917255919 owner's manual.
What “18 HP twin-cylinder” means for this tractor
A twin-cylinder riding mower engine typically runs smoother than a single-cylinder engine and holds power better under load (thick grass, hills, or pulling attachments).
Common benefits you will notice:
- Smoother operation with less vibration at the seat and steering wheel
- Better torque feel when the mower deck is engaged
- More consistent cutting in heavier grass
- Stronger performance for yard and garden attachments
- Easier speed control when conditions change
Quick spec snapshot (what we can confirm vs. what varies)
| Item | What applies to model 917255919 | Why it matters |
|---|---|---|
| Engine type | 18 HP twin-cylinder | Power and smoothness under load |
| Tractor class | GT (garden tractor) | Built for mowing plus attachment work |
| Transmission | All-gear transaxle (6 forward, 2 reverse) | Helps match ground speed to terrain |
| Safety equipment | Deflector shield or grass catcher required when mowing | Reduces thrown-object risk |
If you are trying to identify the exact engine brand or model
On older Craftsman tractors, the engine manufacturer and engine model are usually shown on the engine shroud, valve cover area, or an engine ID label.
We recommend these checks:
- Look for an engine ID tag near the starter, blower housing, or valve cover
- Record the engine model, type, and code (if listed)
- Confirm the tractor model and serial number from the fender-mounted model plate
- Compare the engine ID information to the engine section in the 917255919 owner's manual
Why it matters
Knowing the engine type helps you buy the right maintenance parts (spark plugs, air filter, fuel system parts) and follow the correct tune-up and safety procedures, especially around the muffler, spark arrester, and governor settings.
Last updated: February 2026
What brand engine does Craftsman use?
For Craftsman model 917255919, the engine brand is Briggs & Stratton; the tractor’s manual lists a Briggs & Stratton engine with model number 422437 (type 1256-01). For other Craftsman tractors, the engine brand can vary by model and production year.
What this means for your 917255919
When you’re buying tune-up parts or looking up engine specs, use the Briggs & Stratton identifiers from the tractor documentation.
- Engine manufacturer: Briggs & Stratton
- Engine model number: 422437
- Engine type number: 1256-01
- Best reference for exact specs and service points: 917255919 owner’s manual
Quick ID table (use this when ordering engine parts)
| Item | What to look for | Why it matters |
|---|---|---|
| Tractor model | 917255919 | Ensures chassis and drive parts match |
| Engine brand | Briggs & Stratton | Determines correct engine parts catalog |
| Engine model/type | 422437 / 1256-01 | Narrows to the correct carburetor, gaskets, seals, etc. |
Where to find the engine information on the tractor
We recommend confirming the numbers on the tractor before ordering.
- Check the model plate on the fender for the tractor model and serial number
- Check the engine label/stamping for the Briggs & Stratton model and type
- Record the numbers for future maintenance and parts lookups
Why it matters
Craftsman is the tractor brand, but engines are sourced from engine manufacturers. Using the correct engine brand and model/type prevents wrong-part returns, especially for carburetor, air cleaner, ignition, and gasket sets.
Last updated: February 2026
How much does it cost to replace a riding mower engine?
Replacing the engine on a Craftsman riding mower like model 917255919 typically costs $800 to $2,500 total (engine plus labor), depending on horsepower, crankshaft style, and whether you do the work yourself. If the tractor also needs belts, wiring, or fuel-system work, the total can run higher.
What drives the price
- Engine type and specs: V-twin engines and higher HP cost more than single-cylinder engines.
- Crankshaft configuration: Shaft diameter/length and keyway or tapped shaft must match your pulleys and PTO setup.
- Labor vs. DIY: Shop labor is often the biggest variable.
- Extra parts discovered during teardown: Common add-ons include a drive belt, blade belt, or electrical switches.
- Fuel system condition: Old fuel can create gum and corrosion issues; the manual emphasizes preventing deposits and managing ethanol-blended fuel during storage.
Typical cost ranges (parts and labor)
| Scenario | What you’re paying for | Typical total cost |
|---|---|---|
| DIY engine swap | Engine + basic supplies | $600 to $1,600 |
| Shop engine swap | Engine + labor | $1,200 to $2,500 |
| Engine swap plus “while you’re in there” repairs | Engine + labor + belts/switches/fuel parts | $1,500 to $3,000 |
Smart checks before you buy an engine
Use the 917255919 owner’s manual to confirm your tractor’s engine and drive layout, then verify these items before ordering:
- Engine mounting pattern and crankshaft measurements
- Wiring connections (charging circuit, ignition kill wire)
- Muffler and heat shielding condition (important for safe operation)
- Belt routing and pulley alignment
- Fuel tank and fuel line condition (stale fuel and ethanol blends can damage fuel components during storage)
Parts that commonly get replaced during an engine job
These are not always required, but they are frequent “add-on” repairs when symptoms overlap:
- Lawn tractor ignition switch 532365402 (no-crank or intermittent start)
- Lawn tractor seat switch 532421062 (engine dies when you shift or hit bumps)
- Fuel tank 532151346 (leaks, contamination, or damaged fittings)
Why it matters
An engine replacement is only a good value if the rest of the tractor is solid. If the deck, belts, safety interlocks, and fuel system are in good shape, a new engine can restore reliable mowing for years and reduce repeat breakdowns.
Last updated: February 2026
What model number is the Craftsman 42 riding mower?
For the Craftsman riding mower covered by this parts page, the model number is 917.255919 (often written without the dot as 917255919). You can confirm it on the model plate under the seat and in the 917255919 owner's manual.
Where to find the model number on the mower
On Craftsman riding mowers like model 917255919, the model plate is located under the seat. Use the model number from that plate when ordering parts or looking up diagrams.
- Lift the seat and look for the model plate or label
- Write down the full model number exactly as shown
- Use the model number (not deck size) to match parts correctly
- If the label is dirty, wipe it clean so all digits are readable
42-inch deck vs. model number (what’s the difference?)
“42-inch” describes the cutting deck size, not the model identifier. Many Craftsman tractors can share the same deck size but use different belts, pulleys, switches, or fuel system parts.
| What you have | What it tells you | What to use for parts lookup |
|---|---|---|
| 42-inch deck | Cutting width | Helpful, but not enough by itself |
| Model number 917255919 | Exact tractor configuration | Best match for parts and diagrams |
| Part number (example: 110884X) | Exact replacement part | Best match when reordering the same part |
Why it matters
Using the correct model number prevents ordering the wrong ground drive belt, blade drive belt, PTO switch, ignition switch, or safety interlock parts that can vary between similar-looking Craftsman tractors.
If you are replacing common wear items, match by model first, then confirm by part number:
- Lawn tractor blade drive belt 532110884
- Lawn tractor ignition switch 532365402
- Lawn tractor seat switch 532421062
Last updated: February 2026
