MTD
Gas Walk-Behind Mower

Model # 12AVB2R3791 Official MTD gas lawn mower

Here are the diagrams and repair parts for Official MTD 12AVB2R3791 gas lawn mower, 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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Showing 10 of 133 parts  |

Lawn & Garden Equipment Engine Air Filter (replaces 798452, BS-593260)
#NI01

Lawn mower diagram

Air filter

Part #BS-593260

Replaced by #593260

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Manufacturer substitution
This part replaces BS-593260. Substitute parts can look different from the original.
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$16.56
11% OFF Phone Price : $18.56
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Lawn Mower Wheel, 8 x 2-in
#NI16

Lawn mower diagram

Lawn mower wheel, 8 x 2-in

Part #634-05040

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$37.83
24% OFF MSRP : $50.00
In Stock
Lawn Mower Grass Bag Frame (replaces 647-04271, 747-05226)
#NI11

Lawn mower diagram

Lawn mower grass bag frame (replaces 647-04271, 747-05226)

Part #647-04271-0637

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$45.48
13% OFF MSRP : $52.00
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Lawn Mower Mulching Plug Assembly (replaces 987-02516)
#NI13

Lawn mower diagram

Lawn mower mulching plug assembly (replaces 987-02516)

Part #987-02516A

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$26.84
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Lawn Mower Zone Control Cable (replaces 946-04661)
#NI07

Lawn mower diagram

Lawn mower zone control cable (replaces 946-04661)

Part #946-04661A

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$17.02
23% OFF MSRP : $22.00
In Stock
Lawn & Garden Equipment Engine Fuel Tank Cap (replaces 594061, 597414)
#NI10

Lawn mower diagram

Fuel cap

Part #BS-594061

Replaced by #84004416

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Manufacturer substitution
This part replaces BS-594061. Substitute parts can look different from the original.
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$24.22
17% OFF Phone Price : $29.22
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Lawn & Garden Equipment Hex Bolt, 3/8-24 x 1-1/2-in (replaces 910-1044)
#NI06

Lawn mower diagram

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

Part #710-1044

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This item is not returnable
$3.20
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Lawn Mower Wheel (replaces 634-04630)
#NI17

Lawn mower diagram

Lawn mower wheel (replaces 634-04630)

Part #634-05062

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$41.28
22% OFF MSRP : $53.00
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Lawn Mower Grass Bag (replaces 664P05322)
#NI12

Lawn mower diagram

Lawn mower grass bag

Part #664P05322

Replaced by #664P05322A

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Manufacturer substitution
This part replaces 664P05322. Substitute parts can look different from the original.
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Back Order
Lawn Mower Drive Control Cable (replaces 746-04655A, 946-04655)
#NI08

Lawn mower diagram

Lawn mower drive control cable (replaces 746-04655a, 946-04655)

Part #946-04655A

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This item is not returnable
$30.28
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Symptoms for gas walk-behind mowers

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

April 19, 2023

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

April 19, 2023

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

April 19, 2023

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

January 10, 2024

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

January 10, 2024

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

January 10, 2024

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

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 replace a lawn mower spark plug
March 01, 2016

How to replace a lawn mower spark plug

Take a few minutes to replace the spark plug during your lawn mower's annual tune-up or if the spark plug is burnt or cr…

Repair difficulty
Time required
 15 minutes or less
How to replace a lawn mower blade
March 01, 2016

How to replace a lawn mower blade

Check your lawn mower blade regularly and replaced it if it's bent or damaged. …

Repair difficulty
Time required
 15 minutes or less
How to replace a lawn mower flywheel key on a flathead engine
April 01, 2013

How to replace a lawn mower flywheel key on a flathead engine

When you hit a hard object with your mower, the flywheel can shear to protect more expensive components. Learn how to re…

Repair difficulty
Time required
 45 minutes or less

Articles and videos common to all 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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August 11, 2022

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August 05, 2022

Introducing new technical repair content that we’re developing for the Sears Technical Institute

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June 29, 2022

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