Owner’s manual
How do I find MTD replacement parts?
To find the right MTD replacement parts for model 690, start by confirming the exact model and serial number from the model plate under the seat, then match that information to the parts list and diagrams for your tractor. The owner's manual shows where to find the model plate.
- Pivot the seat forward and locate the model plate at the seat pivot bracket.
- Write down the model number (690) and the serial number exactly as shown.
- Use the model-based parts list/diagrams to identify the part by location and description.
- Match fasteners and hardware by size and application (deck, frame, guards), not just by appearance.
- Order the part that matches your tractor’s configuration (attachments and deck size can change what fits).
These are examples of parts available for this MTD 690 page; use the diagrams to confirm fit before ordering:
| What to verify | Where to find it | Why it matters |
|---|---|---|
| Model number | Model plate under seat | Ensures you pull the correct diagrams |
| Serial number | Same model plate | Helps confirm production version |
| Part description and location | Parts diagram | Prevents ordering a similar-looking part |
| Quantity needed | Diagram callouts | Avoids delays and repeat shipping |
MTD lawn tractor parts often look similar across model ranges, but small differences in deck setup, guards, and mounting points can change the correct bolt, screw, belt, or blade hardware. Using the model plate information first prevents wrong-part returns and downtime.
Last updated: February 2026
What are the parts of a lawn mower engine?
On the MTD lawn tractor model 690, the engine is built from a fuel and air system, an ignition system, internal rotating parts, and starting and lubrication components that work together to create power for mowing. For model-specific service intervals and safety steps, use the owner's manual.
- Fuel system: fuel tank, fuel line, fuel filter (if equipped), carburetor
- Air intake: air filter (air cleaner) and intake housing
- Ignition: spark plug(s), ignition coil (magneto), flywheel
- Starting/charging: starter motor or recoil starter (varies by engine), battery (electric start models)
- Internal engine: crankcase, crankshaft, piston, connecting rod, camshaft, valves
- Lubrication/exhaust: oil sump/drain, muffler, cooling fins and shrouds
The manual for this tractor focuses on safe operation and routine checks that protect the engine and starter.
- Use short starting cycles; cranking longer than 15 seconds per minute can damage the starter motor.
- After striking a foreign object: stop the engine, remove the key, and disconnect and ground the spark plug wire before inspecting.
- Keep engine cooling fins and the area around the engine clean to prevent overheating.
- Service the air cleaner about every 10 hours under normal conditions (more often in dust).
- Clean and gap the spark plug(s) once a season; replace at the start of each mowing season.
| Engine part | What it does | Common symptom when it fails/needs service |
|---|---|---|
| Air filter | Keeps dirt out of the engine | Hard starting, black smoke, loss of power |
| Carburetor | Mixes fuel and air | Surging, won’t start, runs rough |
| Spark plug / ignition coil | Creates spark to ignite fuel | No start, misfire |
| Starter motor / battery | Cranks engine | Clicks, slow crank, no crank |
| Oil drain sleeve/valve (if equipped) | Helps drain oil cleanly | Messy oil changes, leaks if damaged |
Knowing the major engine parts helps you troubleshoot faster and avoid damage. For example, keeping cranking time short protects the starter, and cleaning the air filter and cooling fins helps prevent hard-start and overheating problems.
Last updated: February 2026
What is a 690 number?
On this Sears PartsDirect page, 690 is the MTD lawn tractor model series number for the 690 through 699 hydrostatic front-engine tractors. Use it to match the correct parts list and procedures in the owner's manual for your specific tractor in the 690-699 series.
The model number is printed on the tractor’s model plate. Once you locate it, record both the model and serial number for future parts lookups and service.
- Look for a model plate on the tractor frame (commonly under the seat area, near the rear fender, or on the frame rail)
- Clean off grass and dirt so the numbers are readable
- Write down the model series (690-699) and the serial number
- Use the model series to choose the right diagrams for your deck, engine, and chassis
MTD used “690-699” to group several closely related tractors. Parts can vary by deck size, attachments, and production changes, so confirming the exact model plate information helps you avoid ordering the wrong hardware or components.
| Number you see | What it means | How we use it |
|---|---|---|
| 690 | Model series identifier | Points you to the correct 690-699 manual and parts diagrams |
| 690-699 | Model series range | Indicates the manual covers multiple tractors in the same family |
| Serial number | Unique unit identifier | Helps narrow down exact part variations |
If you are doing a small repair on your MTD 690 series tractor, matching fasteners matters. For example, common hardware items like a carriage bolt can be model-specific by length and thread.
- Compare the old fastener to the replacement before installing
- Use the correct wrench size to avoid rounding heads
- Tighten securely but do not strip threads
Using the correct model series number (690-699) keeps your troubleshooting steps, safety guidance, and replacement parts aligned with how your tractor was built.
Last updated: February 2026
