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MTD
Gas Walk-Behind Mower

Model # 12A-446M729 Official MTD lawn mower

Here are the diagrams and repair parts for Official MTD 12A-446M729 lawn mower, as well as links to manuals and error code tables, if available.

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  • In the search box below, enter all or part of the part number or the part’s name.

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

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For DIY troubleshooting advice and repair guides, visit our repair help section.

Owner’s manual

Model diagram and schematic

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ALL PARTS
Showing 10 of 91 parts  |
Blade-21" Mu 742-0741
#62

Mower parts diagram

Blade-21" mu

Part #742-0741

Replaced by #942-0741A

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Manufacturer substitution
This part replaces 742-0741. Substitute parts can look different from the original.
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$29.10
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Cable 37.37 746-1113
#7

Mower parts diagram

Cable 37.37

Part #746-1113

Replaced by #946-1113A

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Manufacturer substitution
This part replaces 746-1113. Substitute parts can look different from the original.
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$23.67
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Knob Wing Nut 720-0284
#12

Mower parts diagram

Knob wing nut

Part #720-0284

Replaced by #720-04072A

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Manufacturer substitution
This part replaces 720-0284. Substitute parts can look different from the original.
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$9.33
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Lawn Tractor Screw, 1/4-20 X 5/8-in (replaces 910-1652) 710-1652
#30

Mower parts diagram

Lawn tractor screw, 1/4-20 x 5/8-in (replaces 910-1652)

Part #710-1652

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$5.44
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Wheel Asm-8 634-0190
#88C

Mower parts diagram

Wheel asm-8

Part #634-0190

Replaced by #634-0190A

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Manufacturer substitution
This part replaces 634-0190. Substitute parts can look different from the original.
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$34.92
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Yard Machines Lawn Mower Wheel 734-1987
#88D

Mower parts diagram

Yard machines lawn mower wheel

Part #734-1987

$26.80
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Wing Nut 712-0397
#33

Mower parts diagram

Wing nut

Part #712-0397

Replaced by #712-0397A

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Manufacturer substitution
This part replaces 712-0397. Substitute parts can look different from the original.
This item is not returnable
$5.22
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Complete Wheel 734-2004A
#88I

Mower parts diagram

Complete wheel

Part #734-2004A

Replaced by #753-08093

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Manufacturer substitution
This part replaces 734-2004A. Substitute parts can look different from the original.
$46.07
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Complete Wheel 734-2005A
#88G

Mower parts diagram

Complete wheel

Part #734-2005A

Replaced by #753-08093

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Manufacturer substitution
This part replaces 734-2005A. Substitute parts can look different from the original.
$46.07
| 
12% OFF Phone Price : $52.07
In Stock
Lawn Tractor Push Cap 726-0201
#91

Mower parts diagram

Lawn tractor push cap

Part #726-0201

This item is not returnable
$10.56
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In Stock

Symptoms for gas walk-behind mowers

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

View all

Why does my lawn mower vibrate a lot?

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

Read more

Why does my lawn mower cut unevenly?

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

Read more

Why does my lawn mower run rough?

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

Read more

Why won't my lawn mower move?

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

Read more

Why won't my lawn mower start?

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

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Why does my lawn mower stall?

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

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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.

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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....

Read more
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....

Read more
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....

Read more
Repair difficulty
Time required
15 minutes or less

Effective articles & videos to help repair your walk-behind mowers

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

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How to enjoy all the online benefits we offer on our Sears PartsDirect website

How to enjoy all the online benefits we offer on our Sears PartsDirect website

Learn about all the convenient features on our Sears PartsDirect website that make your parts purchases easier....

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Top questions about Sears and Sears PartsDirect

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

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Types of walk-behind mower blades video

Types of walk-behind mower blades video

Learn about the different kinds of mower blades and how to maintain them....

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