Owner’s manual
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What kind of engine does a Craftsman riding lawn mower have?
The Craftsman lawn tractor model 917273640 uses a low-emission gasoline engine and is rated at 18.5 HP. It is an electric-start tractor with an automatic transmission and a 42-inch mower deck, as shown in the 917273640 owner's manual.
What “kind of engine” means on this model
On the 917273640, “kind of engine” typically refers to fuel type, emissions design, and how it’s operated.
- Gas-powered, low-emission engine design
- Electric start with an ignition key
- Designed to run at full throttle for best mowing and battery charging
- Uses operator-presence and safety interlock features (seat switch)
- Built to power a 42-inch mower deck for cutting and mulching
Quick specs from the manual
| Spec | Craftsman 917273640 |
|---|---|
| Engine rating | 18.5 HP |
| Starting | Electric start |
| Transmission | Automatic |
| Mower deck | 42 in |
| Emissions note | Low-emission engine (operates differently than older designs) |
Why it matters
Low-emission engines can respond differently than older carbureted designs, especially during starting and warm-up. Following the correct throttle and choke procedure helps prevent hard starting, stalling, and weak cutting performance.
Helpful operating tips (engine performance)
- Start and operate the tractor exactly as outlined in the 917273640 owner's manual.
- Mow at full throttle for best cut quality and proper battery charging.
- Do not use the choke to stop the engine; use the key switch to stop.
- Avoid idling on grass; hot exhaust can brown turf.
- If grass is very tall, mow twice (first pass higher, second pass to finish height).
Last updated: February 2026
Is it worth replacing a lawn mower engine?
Yes, replacing the engine on your Craftsman lawn tractor model 917273640 is worth it when the tractor is otherwise in good shape and you want to extend its service life; it is usually not worth it when the engine swap plus needed tune-up parts approaches about half the cost of a comparable replacement tractor.
Quick decision checklist
- The deck, transmission, and steering are solid (no major failures)
- You can do the work yourself or have a reasonable labor quote
- You plan to keep the tractor for multiple seasons
- The engine failure is major (thrown rod, no compression, severe smoking)
- You have recurring maintenance issues that point to neglect (dirty cooling fins, old fuel, worn belts)
Costs and effort: what to compare
Engine replacement cost is only part of the decision. We recommend comparing the full “back to reliable” cost.
| Item to compare | Replace engine | Replace tractor |
|---|---|---|
| Upfront cost | Medium to high | High |
| Time to complete | 1 day to a weekend | Same day |
| Risk of other failures | Medium (older belts, blades, battery) | Low (new machine) |
| Long-term value | High if rest of tractor is strong | High if you need upgrades |
If you keep the tractor: maintenance that protects the new engine
Your 917273640 manual calls out routine items that directly affect engine life, including keeping the cooling system clear, replacing the spark plug and air filter regularly, and replacing the in-line fuel filter once each season. Use the 917273640 owner's manual to follow the maintenance schedule and safety steps.
- Clean chaff and debris from the engine cooling area to prevent overheating
- Replace the spark plug at the start of the mowing season or every 100 hours
- Replace the in-line fuel filter once each season
- Check engine oil level before each use
- Keep nuts and bolts tight; never adjust or repair with the engine running
Why it matters
An engine swap can be a smart investment, but only if the rest of the tractor is safe and dependable. If the deck and drive system are worn, you can end up chasing problems after the engine is replaced. For cut quality, also plan on inspecting blades and belts at least yearly; a worn blade drive belt such as the Craftsman lawn tractor blade drive belt, 5/8 x 97-2/5-in 532174883 can reduce performance even with a strong engine.
Last updated: February 2026
What year did Craftsman make the 917273640?
Craftsman model 917273640 is an LT1000-series front-engine lawn tractor that was produced in the early 1990s, with this model commonly tied to 1991 production. For the most accurate date range, match the product ID and decal information in the 917273640 owner's manual.
How to confirm the build year on your tractor
We recommend using the tractor’s identification labels and the manual’s model-specific parts listings to confirm the exact year your unit was built.
- Check the model and serial tag (typically under the seat or on the frame near the rear fender area).
- Record the serial number exactly as shown.
- Compare the engine model listed for 917273640 (Briggs model family is shown in the manual) to what is on your engine shroud.
- Verify the decal set and chassis parts list for model 917273640 in the manual.
- If the tractor has had major repairs, note any swapped assemblies (hood, fender, deck) that could confuse identification.
What the manual tells us for model 917273640
The documentation we have is a model-specific parts manual that identifies the tractor as MODEL NUMBER 917.273640 and lists assemblies like chassis, wheels and tires, and engine components. That confirms the model identity, but the manual itself is not a date stamp.
| What you check | Where to find it | What it helps confirm |
|---|---|---|
| Model number (917273640) | ID tag on frame | Correct tractor family |
| Serial number | Same ID tag | Build date decoding |
| Engine model number | Engine shroud/valve cover | Original engine match |
| Decals and dash panel style | Hood/dash area | Production-era clues |
Why it matters
The exact year affects parts compatibility for common repairs like deck service, belt routing, and safety switch replacements. Confirming the build year helps ensure you get the right blade, belt, or PTO switch for your Craftsman lawn tractor.
Last updated: February 2026
How to find Craftsman riding mower serial number?
On the Craftsman lawn tractor model 917273640, the model and serial number label is typically on the tractor frame under the seat or on the underside of the seat itself. Use that information to match the correct parts and diagrams in the 917273640 owner's manual.
Where to look (fast checklist)
- Park on a flat surface, set the parking brake, and remove the key.
- Tilt the seat forward and look at the frame rails directly under the seat.
- Check the underside of the seat pan for a sticker or metal tag.
- Wipe off grass and dirt; the label is often hard to read when dusty.
- Write down the full model number and serial number exactly as shown.
What the numbers mean
| Item | What it’s used for | Why you need it |
|---|---|---|
| Model number (example: 917273640) | Identifies the tractor configuration | Ensures you get the right belts, blades, and deck parts |
| Serial number | Identifies the production run | Helps confirm the correct version when parts changed mid-series |
Why it matters
Many Craftsman riding mowers share similar frames and 42-inch mower deck layouts, but parts like blades, mandrel components, and drive belts can vary by series. Using the exact model and serial number helps us match the correct diagrams and avoid ordering the wrong replacement.
Related part-matching tip for this model
If you are shopping for mower deck parts after you find the ID tag, match the deck/blade style to the parts list in the manual. For example, this model lists a 42-inch mulching blade option such as the husqvarna lawn tractor mulching blade, 21-in 532134149 in the mower deck section.
Last updated: February 2026
What model number is the Craftsman 917273640 engine?
The Craftsman lawn tractor model 917273640 uses a Briggs engine model 31P777 with type number 0348-E1. You can confirm this in the engine breakdown section of the 917273640 owner's manual.
Where to find the engine model number
You will typically see the engine identification stamped or labeled on the engine itself. Common locations include:
- On the valve cover
- On the blower housing (recoil or fan shroud area)
- Near the spark plug wire
- On a label near the muffler or fuel tank
- On the engine block near the starter
What the numbers mean (so you order the right parts)
For this tractor, the manual lists the engine as 31P777-0348-E1. Use these identifiers when matching Briggs parts such as air filters, carburetor kits, and ignition components.
| Identifier | What it identifies | Example for this tractor |
|---|---|---|
| Tractor model number | The Craftsman tractor platform | 917273640 |
| Engine model number | The Briggs engine family | 31P777 |
| Type number | Exact engine build configuration | 0348-E1 |
Why it matters
Many Craftsman riding mowers share similar frames and decks, but engine parts can vary by Briggs model and type. Using 31P777 and 0348-E1 prevents ordering the wrong tune-up or fuel system parts.
Related parts and maintenance tips
If you are troubleshooting performance or cut quality, these common service areas help:
- Replace worn blades if the cut is ragged (consider husqvarna lawn tractor mulching blade, 21-in 532134149 or lawn tractor 42-in deck high-lift blade 532138971 if they match your deck setup)
- Inspect deck drive components if blades slip or squeal
- Check the PTO switch if the blades will not engage
- Keep the air filter clean and fuel fresh
Last updated: February 2026
How much does it cost to replace a riding mower engine?
For a Craftsman lawn tractor like model 917273640, replacing the engine typically costs $800 to $2,500 total (engine plus labor), depending on horsepower, crankshaft style, and whether you do the work yourself or hire a shop. In many cases, a full engine swap costs more than major belt or deck repairs.
What drives the price most
- Engine type and specs: single-cylinder vs V-twin, horsepower, and crankshaft diameter/length.
- Labor time: engine removal, wiring, throttle/choke linkage, fuel line, and exhaust transfer.
- Extra parts you may need: new belts, pulleys, hardware, or a PTO clutch if worn.
- Shop rates: local labor rates and minimum service charges.
- Condition of the tractor: rusted fasteners, damaged wiring, or worn deck components add time.
Typical cost ranges (parts and labor)
| Scenario | What you pay for | Typical total cost |
|---|---|---|
| DIY engine swap | Engine + incidentals | $500 to $1,500 |
| Shop-installed engine | Engine + labor | $800 to $2,500 |
| “While you’re in there” repairs | Belts, blades, deck parts | +$50 to $400 |
When an engine replacement makes sense
Engine replacement is usually worth it when the tractor’s deck, transmission, and steering are in good shape and you want to extend service life.
A quick value check on common wear items:
- If the deck won’t spin due to a worn belt, a blade drive belt such as the Craftsman lawn tractor blade drive belt, 5/8 x 97-2/5-in 532174883 can be far less expensive than an engine.
- If the tractor has loss of drive, a ground belt like the lawn tractor ground drive belt, 1/2 x 82-in 532140294 is a common fix.
- If cut quality is poor, replacing blades such as the lawn tractor 42-in deck high-lift blade 532138971 can restore performance.
Why it matters
An engine swap is a big investment; checking the deck, belts, battery/starting system, and safety circuits first prevents spending engine money on a tractor that really needs a simpler repair. The troubleshooting chart in the 917273640 owner's manual is a solid starting point for separating engine problems from drive or deck problems.
Last updated: February 2026
