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MTD
Gas Walk-Behind Mower

Model # 11A-B21K799 Official MTD lawn mower

Here are the diagrams and repair parts for Official MTD 11A-B21K799 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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Owner’s manual
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Model diagram and schematic

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ALL PARTS
Showing 10 of 135 parts  |
Upper Handle 749-04681-0637
#2

Lawn mower diagram

Upper handle

Part #749-04681-0637

Replaced by #749-05084B-0637

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Manufacturer substitution
This part replaces 749-04681-0637. Substitute parts can look different from the original.
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$39.50 | 
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Lawn Mower Side Chute Deflector 731-07486
#10

Lawn mower diagram

Lawn mower side chute deflector

Part #731-07486

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Lawn Mower Blade Support (replaces 936-0524a) 736-0524B
#31

Lawn mower diagram

Lawn mower blade support (replaces 936-0524a)

Part #736-0524B

Replaced by #736-0524B-1

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Manufacturer substitution
This part replaces 736-0524B. Substitute parts can look different from the original.
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$6.58 | 
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Yard Machines Lawn & Garden Equipment Nut 712-04064
#32

Lawn mower diagram

Yard machines lawn & garden equipment nut

Part #712-04064

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$4.49 | 
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Yard Machines Lawn & Garden Equipment Hex Bolt, 3/8-24 X 1-1/2-in (replaces 910-1044) 710-1044
#25

Lawn mower diagram

Yard machines lawn & garden equipment hex bolt, 3/8-24 x 1-1/2-in (replaces 910-1044)

Part #710-1044

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Lawn Mower Blade Adapter 748-04096
#23

Lawn mower diagram

Lawn mower blade adapter

Part #748-04096

Replaced by #753-06304

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Manufacturer substitution
This part replaces 748-04096. Substitute parts can look different from the original.
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Lawn Mower Wheel, Rear, 11-in 634-04630
#33

Lawn mower diagram

Lawn mower wheel, rear, 11-in

Part #634-04630

Replaced by #634-05062

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Manufacturer substitution
This part replaces 634-04630. Substitute parts can look different from the original.
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Lawn Mower Lower Handle 749-04608A-0637
#4

Lawn mower diagram

Lawn mower lower handle

Part #749-04608A-0637

Replaced by #749-07298-0637

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Manufacturer substitution
This part replaces 749-04608A-0637. Substitute parts can look different from the original.
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Lawn & Garden Equipment Flange Nut 712-04217
#28

Lawn mower diagram

Lawn & garden equipment flange nut

Part #712-04217

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Lawn & Garden Equipment Shoulder Screw (replaces 738-04419) 738-04419A
#27

Lawn mower diagram

Lawn & garden equipment shoulder screw (replaces 738-04419)

Part #738-04419A

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$5.58 | 
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Symptoms for gas walk-behind mowers

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

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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…

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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…

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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

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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