MTD
Lawn & Garden Engine

Model # 478-SUC Official MTD engine

Here are the diagrams and repair parts for Official MTD 478-SUC engine, as well as links to manuals and error code tables, if available.

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Not all parts are shown on the diagrams—those parts are labeled NI, for “not illustrated”.

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Model diagram and schematic

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ALL PARTS
Showing 10 of 141 parts  |

Lawn & Garden Equipment Engine Spark Plug 951-10292
#148

Cylinder head diagram

Lawn & garden equipment engine spark plug

Part #951-10292

Replaced by #951-10292A

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Manufacturer substitution
This part replaces 951-10292. Substitute parts can look different from the original.
BEST SELLER
This item is not returnable
$5.88
15% OFF Phone Price : $6.88
Back Order
Lawn & Garden Equipment Engine Starter Key (replaces 731-05632, 751-10630) 951-10630
#6

Muffler & controls diagram

Lawn & garden equipment engine starter key (replaces 731-05632, 751-10630)

Part #951-10630

BEST SELLER
$8.44
11% OFF Phone Price : $9.44
In Stock
Lawn & Garden Equipment Engine Carburetor Float Bowl Gasket 951-11349
#Y

Carburetor diagram

Lawn & garden equipment engine carburetor float bowl gasket

Part #951-11349

Replaced by #951-11349A

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Manufacturer substitution
This part replaces 951-11349. Substitute parts can look different from the original.
This item is not returnable
$5.64
15% OFF Phone Price : $6.64
In Stock
Snowblower Carburetor Gasket (replaces 751-11223) 951-11223
#171

Carburetor diagram

Snowblower carburetor gasket (replaces 751-11223)

Part #951-11223

This item is not returnable
$8.09
11% OFF Phone Price : $9.09
In Stock
Snowblower Ignition Switch (replaces 751-10637, 925-04031a) 951-10637
#5

Muffler & controls diagram

Snowblower ignition switch (replaces 751-10637, 925-04031a)

Part #951-10637

This item is not returnable
$18.67
10% OFF Phone Price : $20.67
In Stock
Lawn & Garden Equipment Engine Carburetor Primer Bulb 951-11824
#174

Carburetor diagram

Lawn & garden equipment engine carburetor primer bulb

Part #951-11824

This item is not returnable
$17.13
10% OFF Phone Price : $19.13
In Stock
Craftsman Snowblower Recoil Starter Assembly (replaces 751-11208) 951-11208
#128

Starter/blower housing diagram

Craftsman snowblower recoil starter assembly (replaces 751-11208)

Part #951-11208

$88.72
6% OFF Phone Price : $94.72
In Stock
Lawn & Garden Equipment Engine Flywheel Key 951-10307
#90

Crankcase diagram

Lawn & garden equipment engine flywheel key

Part #951-10307

Replaced by #751P10307A

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Manufacturer substitution
This part replaces 951-10307. Substitute parts can look different from the original.
This item is not returnable
$3.22
24% OFF Phone Price : $4.22
In Stock
Lawn & Garden Equipment Engine Valve Retainer 951-12080
#155

Cylinder head diagram

Lawn & garden equipment engine valve retainer

Part #951-12080

This item is not returnable
$6.47
13% OFF Phone Price : $7.47
In Stock
Lawn & Garden Equipment Engine Rocker Arm 951-11966
#159

Cylinder head diagram

Lawn & garden equipment engine rocker arm

Part #951-11966

This item is not returnable
$12.82
13% OFF Phone Price : $14.82
In Stock

Symptoms for gas walk-behind mowers

Choose a symptom to see related walk-behind mower repairs.

Main causes: damaged cutting blade, loose cutting blade, damaged flywheel key, engine needs tune up…

Main causes: uneven wheel height settings, damaged wheel, dull or damaged cutting blade…

Main causes: engine needs tune up, dirty or clogged carburetor, damaged flywheel key…

Main causes: drive control cable failure, worn or broken drive belt, bad transmission, broken drive wheel…

Main causes: stale gas, engine needs tune up, bad spark plug, dead battery, bad recoil starter, faulty safety switch, ba…

Main causes: dirty carburetor, bad spark plug, clogged air filter, engine choke problems, clogged gas cap vent…

Repair guides for gas walk-behind mowers

These step-by-step repair guides will help you safely fix what’s broken on your walk-behind lawn mower.

How to rebuild a lawn mower carburetor

How to rebuild a lawn mower carburetor

The carburetor mixes air with fuel to drive the piston. Rebuild the carburetor if it's clogged or leaks.…

Repair difficulty
Time required
 60 minutes or less
How to replace a lawn mower recoil starter on an OHV engine

How to replace a lawn mower recoil starter on an OHV engine

Replace the recoil starter if it doesn't move when you pull the starter rope.…

Repair difficulty
Time required
 15 minutes or less
How to replace a lawn mower wheel

How to replace a lawn mower wheel

Learn how replace a damaged wheel on a walk-behind lawn mower—it's a quick, easy fix.…

Repair difficulty
Time required
 15 minutes or less

Effective articles & videos to help repair your lawn & garden engines

Use the advice and tips in these articles and videos to get the most out of your walk-behind lawn mower.

Top questions about Sears and Sears PartsDirect

Top questions about Sears and Sears PartsDirect

Get answers to frequently asked questions about Sears and Sears PartsDirect.…

What are the main components of a lawn mower?

What are the main components of a lawn mower?

Learn about the main parts of a lawn mower and when to replace parts.…