Briggs & Stratton
Lawn & Garden Engine

Model # 120202-3780-B1 Official Briggs & Stratton engine

Here are the diagrams and repair parts for Official Briggs & Stratton 120202-3780-B1 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 159 parts  |

Lawn & Garden Equipment Engine Air Filter (replaces 17211-2l8-000, 1759330, 1904481, 491588, 491588ms, 494245, 6.491-338, 691710, Bs-491588s) 491588S

#445

All parts diagram

Lawn & garden equipment engine air filter (replaces 17211-2l8-000, 1759330, 1904481, 491588, 491588ms, 494245, 6.491-338, 691710, bs-491588s)

Part #491588S

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Lawn & Garden Equipment Engine Recoil Starter Pulley (replaces 263074, 281504, Bs-498144) 498144
Lawn & garden equipment engine recoil starter pulley (replaces 263074, 281504, bs-498144)

Part #498144

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Lawn & Garden Equipment Engine Carburetor Fuel Inlet Fitting (replaces 493496, Bs-692317) 692317

#186

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Lawn & garden equipment engine carburetor fuel inlet fitting (replaces 493496, bs-692317)

Part #692317

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Lawn & Garden Equipment Engine Flywheel Key (replaces 222698, 690974, Bs-222698s) 222698S

#24

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Lawn & garden equipment engine flywheel key (replaces 222698, 690974, bs-222698s)

Part #222698S

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Pre-filter 493537

#967

All parts diagram

Pre-filter

Part #493537

Replaced by #493537S

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This part replaces 493537. Substitute parts can look different from the original.
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Fuel Tank 694260

#972

All parts diagram

Fuel tank

Part #694260

Replaced by #799863

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This part replaces 694260. Substitute parts can look different from the original.
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Lawn & Garden Equipment Engine Carburetor Needle Valve (replaces 281144, 281178, Bs-398188) 398188

#134

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Lawn & garden equipment engine carburetor needle valve (replaces 281144, 281178, bs-398188)

Part #398188

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Lawn & Garden Equipment Engine Recoil Starter Pawl (replaces 281505, 692260, Bs-281505s) 281505S

#459

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Lawn & garden equipment engine recoil starter pawl (replaces 281505, 692260, bs-281505s)

Part #281505S

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Lawn & Garden Equipment Engine Recoil Starter Pawl Friction Plate (replaces 281503, Bs-692299) 692299

#456

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Lawn & garden equipment engine recoil starter pawl friction plate (replaces 281503, bs-692299)

Part #692299

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Lawn & Garden Equipment Engine Recoil Starter Rope (replaces 693449, Bs-693389) 693389

#58

All parts diagram

Lawn & garden equipment engine recoil starter rope (replaces 693449, bs-693389)

Part #693389

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Symptoms for gas walk-behind mowers

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

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…

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

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…

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

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

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

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

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.…