Tecumseh
Lawn & Garden Engine

Model # TYPE 643-20C Official Tecumseh engine

Here are the diagrams and repair parts for Official Tecumseh TYPE-643-20C engine, as well as links to manuals and error code tables, if available.

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Model diagram and schematic

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ALL PARTS
Showing 10 of 119 parts  |

Cover 610118
#43

Basic engine diagram

Cover

Part #610118

The manufacturer no longer makes this part, and there's no substitute part

Bowl Gasket 631334
#21

Carburetor diagram

Bowl gasket

Part #631334

The manufacturer no longer makes this part, and there's no substitute part

Spring 630766
#59

Basic engine diagram

Spring

Part #630766

The manufacturer no longer makes this part, and there's no substitute part

Rewnd Startr 590420
#74

Basic engine diagram

Rewnd startr

Part #590420

The manufacturer no longer makes this part, and there's no substitute part

Gasket 510217
#29

Basic engine diagram

Gasket

Part #510217

The manufacturer no longer makes this part, and there's no substitute part

Gasket 510274
#18

Basic engine diagram

Gasket

Part #510274

The manufacturer no longer makes this part, and there's no substitute part

Piston 310230
#5

Basic engine diagram

Piston

Part #310230

The manufacturer no longer makes this part, and there's no substitute part

Pistn Rng St 310190
#6

Basic engine diagram

Pistn rng st

Part #310190

The manufacturer no longer makes this part, and there's no substitute part

Screw 650506
#4

Carburetor diagram

Screw

Part #650506

The manufacturer no longer makes this part, and there's no substitute part

Brake Spring 590411
#3

Rewind starter diagram

Brake spring

Part #590411

The manufacturer no longer makes this part, and there's no substitute part

Symptoms for gas walk-behind mowers

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

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

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

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

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

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

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

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 transmission

How to replace a lawn mower transmission

Learn how to replace the transmission on your lawn mower if it's locked up or won't drive the wheels.…

Repair difficulty
Time required
 60 minutes or less
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.…

Repair difficulty
Time required
 60 minutes or less
How to replace a lawn mower ignition coil on a flathead engine

How to replace a lawn mower ignition coil on a flathead engine

If the spark plug doesn't fire when you try to start the mower, you could have a defective ignition coil. Follow these s…

Repair difficulty
Time required
 30 minutes or less

Effective articles & videos to help repair your lawn & garden engines

Use the advice and tips in these articles and videos to get the most out of your walk-behind lawn mower.

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.…

What are the main components of a lawn mower?

What are the main components of a lawn mower?

Learn about the main parts of a lawn mower and when to replace parts.…