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MTD
Rear-Tine Tiller

Model # 21A-450 Official MTD rear tine gas tiller

Here are the diagrams and repair parts for Official MTD 21A-450 rear tine gas tiller, as well as links to manuals and error code tables, if available.

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Owner’s manual

Model diagram and schematic

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Showing 10 of 161 parts  |
Lawn Tractor Screw (replaces 01000628, 01000865, 1186307, 1186308, 791-180288, 791-683298, 910-0599) 710-0599
Lawn tractor screw (replaces 01000628, 01000865, 1186307, 1186308, 791-180288, 791-683298, 910-0599)

Part #710-0599

BEST SELLER
This item is not returnable
$4.91 | 
17% OFF Phone Price : $5.91
In Stock
Yard Machines Lawn & Garden Equipment Bell Washer (replaces 936-0242) 736-0242
Yard machines lawn & garden equipment bell washer (replaces 936-0242)

Part #736-0242

BEST SELLER
This item is not returnable
$6.58 | 
13% OFF Phone Price : $7.58
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Lock Washer 736-0119
#12

Outer and inner engine pulley/wheels diagram

Lock washer

Part #736-0119

Replaced by #936-0119

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Manufacturer substitution
This part replaces 736-0119. Substitute parts can look different from the original.
This item is not returnable
$6.05 | 
14% OFF Phone Price : $7.05
In Stock
Ryobi Lawn Tractor Bolt (replaces 01000369, 1509-091, 1509-117, 153015, 706-10123-20, 706-501277-1, 710-0342, 910-3005) 710-3005
#4

Handle/tine adapter/shield diagram

Ryobi lawn tractor bolt (replaces 01000369, 1509-091, 1509-117, 153015, 706-10123-20, 706-501277-1, 710-0342, 910-3005)

Part #710-3005

This item is not returnable
$5.11 | 
16% OFF Phone Price : $6.11
In Stock
Ryobi Lawn & Garden Equipment Flat Washer 736-0204
#63

Handle/tine adapter/shield diagram

Ryobi lawn & garden equipment flat washer

Part #736-0204

This item is not returnable
$5.43 | 
16% OFF Phone Price : $6.43
In Stock
Lawn Tractor Hex Bolt 710-3008
Lawn tractor hex bolt

Part #710-3008

This item is not returnable
$4.62 | 
18% OFF Phone Price : $5.62
In Stock
Ace Lawn & Garden Equipment Flange Lock Nut 712-3004A
Ace lawn & garden equipment flange lock nut

Part #712-3004A

This item is not returnable
$4.92 | 
17% OFF Phone Price : $5.92
In Stock
Ryobi Lawn & Garden Equipment Flat Washer 736-3088
#37

Gear case assembly diagram

Ryobi lawn & garden equipment flat washer

Part #736-3088

This item is not returnable
$6.17
In Stock
Ryobi Tiller Shift Rod Knob 720-0210A
#11

Handle/tine adapter/shield diagram

Ryobi tiller shift rod knob

Part #720-0210A

This item is not returnable
$26.46
In Stock
Ryobi Tiller Wheel Axle Oil Seal 721-0379
#29

Gear case assembly diagram

Ryobi tiller wheel axle oil seal

Part #721-0379

This item is not returnable
$23.80 | 
20% OFF Phone Price : $29.80
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…

Read more

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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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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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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