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MTD
Rear-Tine Tiller

Model # 21AA412A000 Official MTD rear-tine tiller

Here are the diagrams and repair parts for Official MTD 21AA412A000 rear-tine tiller, 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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Owner’s manual

Model diagram and schematic

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Showing 10 of 134 parts  |
Yard Machines Lawn & Garden Equipment Nut 712-04064
#15

Drive system diagram

Yard machines lawn & garden equipment nut

Part #712-04064

BEST SELLER
This item is not returnable
$4.16 | 
19% OFF Phone Price : $5.16
Back Order
Bearing 741-0124
#34

Gear case diagram

Bearing

Part #741-0124

Replaced by #941-0600

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Manufacturer substitution
This part replaces 741-0124. Substitute parts can look different from the original.
BEST SELLER
$26.71 | 
18% OFF Phone Price : $32.71
In Stock
Ryobi Lawn Tractor Screw 710-0376
#37

Handle & tine shield diagram

Ryobi lawn tractor screw

Part #710-0376

This item is not returnable
$5.11 | 
16% OFF Phone Price : $6.11
In Stock
Toro Lawn & Garden Equipment Lock Washer (replaces 936-0169) 736-0169
#38

Handle & tine shield diagram

Toro lawn & garden equipment lock washer (replaces 936-0169)

Part #736-0169

This item is not returnable
$4.89
In Stock
Lawn Tractor Hex Bolt 710-3008
Lawn tractor hex bolt

Part #710-3008

This item is not returnable
$4.31 | 
19% OFF Phone Price : $5.31
In Stock
Push Cap 726-0106
#25

Handle & tine shield diagram

Push cap

Part #726-0106

Replaced by #726-0106

?
Manufacturer substitution
This part replaces 726-0106. Substitute parts can look different from the original.
This item is not returnable
$2.16
In Stock
Depth Bar Assembly 786-0120
#43

Handle & tine shield diagram

Depth bar assembly

Part #786-0120

Replaced by #786-0120-0637

?
Manufacturer substitution
This part replaces 786-0120. Substitute parts can look different from the original.
$85.29 | 
7% OFF Phone Price : $91.29
In Stock
Shaft Seal 721-0378
#1

Gear case diagram

Shaft seal

Part #721-0378

Replaced by #921-0378

?
Manufacturer substitution
This part replaces 721-0378. Substitute parts can look different from the original.
This item is not returnable
$24.37 | 
20% OFF Phone Price : $30.37
In Stock
Yard Machines Lawn & Garden Equipment Washer (replaces 936-0105) 736-0105
#27

Drive system diagram

Yard machines lawn & garden equipment washer (replaces 936-0105)

Part #736-0105

This item is not returnable
$5.83
In Stock
Ryobi Lawn & Garden Equipment Flat Washer 736-0407
#3

Gear case diagram

Ryobi lawn & garden equipment flat washer

Part #736-0407

This item is not returnable
$5.34
In Stock

Most common symptoms to help you fix your tillers

Choose a symptom to see related tiller repairs.

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Why do my tiller's tines turn but the wheels don't?

Main causes: clutch cable problems, faulty transmission…

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Why does my tiller turn the soil poorly?

Main causes: damaged tines, broken clevis pins, worn drive belt, faulty transmission, clutch cable problems, improper de…

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Why won't my tillers wheels or tines turn?

Main causes: worn or broken drive belts, bad transmission, clutch cable problems…

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Why does my tiller's engine leak oil or gas?

Main causes: leaky engine head gasket, damaged sump gasket, damaged oil drain plug seal, loose or cracked fuel line, lea…

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Why do my tiller's wheels turn but the tines don't?

Main causes: broken shaft clevis pins, transmission failure…

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Why does my tiller's engine run roughly or misfire?

Main causes: dirty carburetor, engine needs tune up, stale gas…

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Why won't my tiller's engine start?

Main causes: carburetor failure, bad gasoline, dirty spark plug, broken recoil starter…

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Most common repair guides to help fix your tillers

These step-by-step repair guides will help you safely fix what’s broken on your tiller.

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How to replace a tiller recoil starter

How to replace a tiller recoil starter

The recoil starter spins the engine when you pull the starter rope, and the rope retracts when released. If the recoil s…

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Repair difficulty
Time required
 15 minutes or less

Effective articles & videos to help repair your tillers

Use the advice and tips in these articles and videos to get the most out of your tiller.

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Find the right carburetor assembly for a Craftsman snowblower, tiller or log splitter

Find the right carburetor assembly for a Craftsman snowblower, tiller or log splitter

This chart will help you find the right carburetor for your Craftsman snowblower, tiller or log splitter.…

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A guide to garden tillers

A guide to garden tillers

Rear tine tiller or front tine tiller, what to know to help in choosing the correct one for your needs.…

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Tiller common questions

Tiller common questions

These frequently asked questions might help you figure out what's wrong with your garden tiller.…

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