MTD 660 THRU 679 lawn tractor Parts

For your MTD model 660 front-engine lawn tractor, the fastest way to find the correct replacement parts is to copy the model and serial information from the model plate (commonly located under the seat), then match that information to the parts diagrams and lists in the 660 owner's manual.

Step-by-step: how we recommend finding the right part

• Locate the model plate and write down the model number and serial number (often under the seat).
• Identify the system you are repairing: mower deck, steering, wheels/tires, engine maintenance, or electrical.
• Use the parts list in the manual to confirm the exact part number for your deck size and configuration.
• Compare your old part to the listing (shape, mounting holes, length, and any stamped numbers).
• Order by part number whenever possible to avoid mismatches.

Common parts people replace on MTD 660 tractors

These are frequent wear items and hardware that often get replaced during routine service:

Part type	What it affects	Example from this model page
Mower blade	Cut quality, vibration	Lawn tractor blade 742-0616
Oil drain valve	Oil change convenience, mess reduction	Oil drain 751-3140
Brake component	Stopping power, parking brake hold	Puck brake 717-0678
Steering component	Steering play, control	Steering shaft (listed as 738-0919)

Why the model and serial number matter

MTD often used multiple deck sizes and configurations across the 660 thru 679 series. The manual parts list calls out different blades, belts, and adapters by deck size (for example, 38-inch, 42-inch, and 46-inch decks). Matching your tractor’s exact configuration prevents ordering a blade, belt, or adapter that will not fit.

Quick tips to avoid ordering the wrong part

• If you are replacing a blade or deck part, confirm your deck size first.
• If the engine will not start, check basics first (fuel supply, fuel line/filter, air filter condition) before ordering parts.
• If you have vibration, stop the engine and inspect blade tightness and spindle/pulley condition before continuing to mow.

Last updated: February 2026

For an MTD lawn tractor like model 660, the most reliable way to identify the year is to record the model and serial information from the model plate (the manual notes it’s located under the seat) and then use that serial data to determine the manufacturing date. See the MTD 660 owner's manual for the model plate location.

Where to find the model plate on MTD 660

On this tractor family, the model plate is typically placed where it stays protected but still readable.

• Park on a level surface, set the parking brake, and remove the key
• Lift the seat and look for a sticker or metal tag underneath
• Write down the model number and serial number exactly as shown
• If the tag is dirty, wipe it gently so every digit is readable
• Take a clear photo for reference when ordering parts or calling for service

What to write down (and why)

The “year” is usually tied to the serial number, not the deck size or engine size.

Item on tag	Example (format)	What it’s used for
Model number	660	Identifies the tractor series
Serial number	Varies	Used to determine build date and correct parts
Product name/series	Varies	Helps confirm you are reading the correct tag

How to use the serial number to determine the year

Once you have the serial number, use it to match the correct production run.

• Compare the serial number to the date coding method shown in the MTD 660 owner's manual
• If the manual doesn’t list a date code chart for your serial format, use the serial number when contacting an MTD-authorized service source
• Use the same model and serial details when ordering common wear items like blades, belts, and steering parts

Why it matters

The build year affects parts compatibility across the 660 thru 679 front-engine tractor range, especially for deck components, steering hardware, and electrical items. Using the model plate information helps ensure you get the correct replacement part the first time.

Last updated: February 2026

A 679cc lawn tractor engine typically falls in the 20 to 24 horsepower range, depending on whether it’s a single-cylinder or V-twin, the governed RPM, and whether the rating is listed as gross or net power. For your MTD model 660 series tractor, confirm the exact rating in the MTD 660 owner’s manual.

What changes horsepower on a 679cc engine?

Displacement (cc) sets the size of the engine, but these factors determine the published horsepower:

• Engine design: V-twin engines commonly rate higher than similar single-cylinder engines
• Governed RPM: higher governed speed increases rated horsepower
• Rating method: gross vs. net ratings can differ by several horsepower
• Tune condition: a dirty air filter, worn spark plug, or stale fuel reduces power
• Operating conditions: high altitude and high heat reduce available power

Typical cc-to-horsepower ranges (lawn tractor engines)

Engine size (cc)	Typical horsepower range
500 to 600	15 to 20 HP
600 to 700	20 to 24 HP
700 to 800	22 to 27 HP

How to confirm the exact horsepower on your tractor

Use the engine identification label, not just the tractor series number.

• Find the engine model/type code on the engine shroud or valve cover area
• Match that code to the specifications information referenced in the MTD 660 owner’s manual
• If the engine was replaced, use the current engine label as the horsepower source
• Mow with the throttle set to FAST to keep blade speed up and reduce engine strain

Why it matters

Horsepower affects how well the tractor holds blade speed in tall grass, how quickly it recovers from heavy cutting loads, and how you diagnose “bogging” complaints that are really tune-up or fuel issues.

Last updated: February 2026

On the MTD lawn tractor model 660, the engine system is built around fuel delivery, air intake, ignition, lubrication, and exhaust components that work together to start, run, and stay protected under load. For model-specific service points and safety steps, use the MTD 660 owner's manual.

Main engine components (what they do)

• Fuel tank and fuel line: stores and delivers gasoline to the carburetor.
• Carburetor: mixes fuel and air for combustion.
• Air filter: keeps dirt out of the engine; a clogged filter can cause hard starting and poor power.
• Ignition system: typically includes the ignition coil and spark plug; the manual calls out seasonal spark plug cleaning and gapping, with replacement recommended at the start of each mowing season.
• Flywheel: helps smooth engine rotation and supports ignition timing.
• Crankcase and internal lubrication: holds oil that protects internal moving parts; your tractor may use an oil drain sleeve or drain setup for easier oil changes.
• Muffler/exhaust: routes exhaust and reduces noise; it gets hot during operation.

Related tractor controls that affect starting and running

Even when the engine is fine, these tractor systems can prevent starting or change how it behaves:

• Ignition switch (key start and stop)
• Clutch-brake pedal (must be depressed to start on many setups)
• Speed control lever and shift linkage (affects ground speed and shifting)
• Safety interlocks/guards (must be in the correct position and working)

Quick “engine system” map

System	Common parts included	What you notice when there’s a problem
Fuel	tank, line, carburetor	cranks but will not start, surging
Air	air filter, intake	black smoke, loss of power
Ignition	spark plug, coil, flywheel	no-start, misfire
Lubrication	oil, drain plug/sleeve	knocking, overheating risk
Exhaust	muffler	loud operation, burning smell

Why it matters

Knowing which system you are dealing with helps you troubleshoot faster and safer. For example, the manual emphasizes removing the spark plug wire before inspecting after striking an object, and keeping fasteners tight to prevent unsafe operation.

Last updated: February 2026

On MTD riding mowers like model 660, the model number is on the model plate located under the seat. Lift the seat and look for the sticker or metal tag; it typically lists both the model and serial information.

Where to look (fast checklist)

• Lift the seat and check the underside area first
• Look for a sticker or metal plate on the seat pan or frame
• Wipe off dirt and grass dust; the print can be hard to read
• Copy the model and serial numbers exactly as shown
• Keep the number handy before ordering parts or calling for service

What the plate usually shows

Most MTD model plates include these fields:

• Model number (used to match parts diagrams)
• Serial number (helps identify production run)
• Sometimes an engine model/type/code (engine parts are often different from tractor parts)

Model number vs. serial number (quick guide)

Item	What it’s used for	Example format
Model number	Matching the correct parts list and diagrams	660
Serial number	Identifying the exact build series	Longer number/letter string
Engine numbers	Finding engine-specific parts and tune-up specs	Separate tag on engine

Why it matters

Using the correct model number prevents ordering the wrong blade, belt, deck, or steering parts. On tractors that share similar frames across multiple series (like 660 thru 679), the model plate is the quickest way to confirm the exact configuration.

For additional identification notes and service info, check the MTD 660 owner’s manual.

Last updated: February 2026