Can’t find your part?   Contact us:
+1-309-603-4777
Sears Parts Direct
Tips to find your model number
Orders

  • Keep track of the models you own in your profile

    Sign in or Register to view or add models

Schedule a repair
MTD
Gas Walk-Behind Mower

Model # 12AE999P099 Official MTD lawn mower

Here are the diagrams and repair parts for Official MTD 12AE999P099 lawn mower, as well as links to manuals and error code tables, if available.

There are a couple of ways to find the part or diagram you need:

  • Click a diagram to see the parts shown on that diagram.
  • 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”.

We encourage you to save the model to your profile, so it’s easy to access parts and manuals for your appliance whenever you log in.

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

Owner’s manual
  View engine

Model diagram and schematic

SEARCH WITHIN THIS MODEL

?

This is the number corresponding to the part on the diagram / schematic

Search
ALL PARTS
Showing 10 of 257 parts  |
Troybilt Lawn Mower 21-in Deck Mulching Blade (replaces 01002810, 742-0741a, 942-04276, 942-0741) 942-0741A
#34

Handle/deck/chute diagram

Troybilt lawn mower 21-in deck mulching blade (replaces 01002810, 742-0741a, 942-04276, 942-0741)

Part #942-0741A

BEST SELLER

Get free shipping with Automatic Reorder

$27.71 | 
18% OFF Phone Price : $33.71
In Stock
Yard Machines Lawn & Garden Equipment Lock Nut, 5/16-18 (replaces 753-05591) 712-04063
Yard machines lawn & garden equipment lock nut, 5/16-18 (replaces 753-05591)

Part #712-04063

BEST SELLER
This item is not returnable
$4.53 | 
18% OFF Phone Price : $5.53
In Stock
Yard Machines Lawn & Garden Equipment Nut 712-04064
#66

Handle/deck/chute diagram

Yard machines lawn & garden equipment nut

Part #712-04064

BEST SELLER
This item is not returnable
$4.49 | 
18% OFF Phone Price : $5.49
In Stock
Yard Machines Lawn Mower Handle Knob (replaces 01000382, 113589, 720-04072, 720-04125) 720-04072A
#13

Handle/deck/chute diagram

Yard machines lawn mower handle knob (replaces 01000382, 113589, 720-04072, 720-04125)

Part #720-04072A

BEST SELLER
$9.33 | 
10% OFF Phone Price : $10.33
In Stock
Lawn & Garden Equipment Wing Nut (replaces 01000203, 912-0397) 712-0397A
#22

Handle/deck/chute diagram

Lawn & garden equipment wing nut (replaces 01000203, 912-0397)

Part #712-0397A

This item is not returnable
$5.22 | 
16% OFF Phone Price : $6.22
In Stock
Lawn & Garden Equipment Wing Nut 912-0397
#51

Drive diagram

Lawn & garden equipment wing nut

Part #912-0397

Replaced by #712-0397A

?
Manufacturer substitution
This part replaces 912-0397. Substitute parts can look different from the original.
This item is not returnable
$5.22 | 
16% OFF Phone Price : $6.22
In Stock
Lawn & Garden Equipment Hex Cap Screw 710-0751
#14

Drive diagram

Lawn & garden equipment hex cap screw

Part #710-0751

This item is not returnable
$5.12 | 
16% OFF Phone Price : $6.12
In Stock
Lawn & Garden Equipment Carriage Bolt (replaces 1186069, 583108, 706-101080, 706-10602-12, 791-182213) 710-0703
#23

Handle/deck/chute diagram

Lawn & garden equipment carriage bolt (replaces 1186069, 583108, 706-101080, 706-10602-12, 791-182213)

Part #710-0703

This item is not returnable
$6.46 | 
13% OFF Phone Price : $7.46
In Stock
Sears Lawn Mower Roller Wheel 756-0625
#60

Handle/deck/chute diagram

Sears lawn mower roller wheel

Part #756-0625

This item is not returnable
$12.00 | 
14% OFF Phone Price : $14.00
In Stock
Lawn & Garden Equipment Cable Tie 725-0157
#47

Drive diagram

Lawn & garden equipment cable tie

Part #725-0157

Replaced by #726-0178

?
Manufacturer substitution
This part replaces 725-0157. Substitute parts can look different from the original.
This item is not returnable
$2.16
In Stock

RECOMMENDED MAINTENANCE PARTS AND ACCESSORIES

Symptoms for gas walk-behind mowers

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

View all

Why does my lawn mower run rough?

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

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 vibrate a lot?

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

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…

Read more

Why does my lawn mower stall?

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

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

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.

View all
How to replace a lawn mower spark plug

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…

Read more
Repair difficulty
Time required
 15 minutes or less
How to replace a lawn mower blade

How to replace a lawn mower blade

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

Read more
Repair difficulty
Time required
 15 minutes or less
How to replace a lawn mower flywheel key on a flathead engine

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…

Read more
Repair difficulty
Time required
 45 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.

View all
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.…

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

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

Learn about Sears Technical Institute and the advanced technical content being developed for aspiring appliance techs.…

Read more
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.…

Read more

Parts & More