Onan
Lawn & Garden Engine

Model # BF-MS2379C Official Onan engine

Here are the diagrams and repair parts for Official Onan BF-MS2379C 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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Showing 10 of 236 parts  |

Element 140-1216
#13

Fuel system group diagram

Element

Part #140-1216

Replaced by #45-083-02-S

?
Manufacturer substitution
This part replaces 140-1216. Substitute parts can look different from the original.
This item is not returnable
$25.09
19% OFF Phone Price : $31.09
In Stock
Lock Nut 870-0277
#19

Crankshaft, flywheel, camshaft and piston group diagram

Lock nut

Part #870-0277

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

Screw 806-0027
#42

Cylinder block group diagram

Screw

Part #806-0027

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

Flat Washer 526-0122
#7

Cylinder block group diagram

Flat washer

Part #526-0122

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

Pre-cleaner 140-1218
#21

Fuel system group diagram

Pre-cleaner

Part #140-1218

Replaced by #45-083-01-S

?
Manufacturer substitution
This part replaces 140-1218. Substitute parts can look different from the original.
This item is not returnable
$7.29
12% OFF Phone Price : $8.29
In Stock
Lock 5/16" - Code 21bj, 21bk, 21bw 850-0045
Lock 5/16" - code 21bj, 21bk, 21bw

Part #850-0045

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

Washer 526-0113
#27

Governor, starter, charging alt. & blower housing group diagram

Washer

Part #526-0113

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

Gear 105-0353
#6

Crankshaft, flywheel, camshaft and piston group diagram

Gear

Part #105-0353

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

Flat Washer 526-0214
#26

Governor, starter, charging alt. & blower housing group diagram

Flat washer

Part #526-0214

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

Flat Washer 526-0018
#5

Cylinder block group diagram

Flat washer

Part #526-0018

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

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

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

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

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 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 recoil starter on an OHV engine

How to replace a lawn mower recoil starter on an OHV engine

Replace the recoil starter if it doesn't move when you pull the starter rope.…

Repair difficulty
Time required
 15 minutes or less
How to replace a lawn mower wheel

How to replace a lawn mower wheel

Learn how replace a damaged wheel on a walk-behind lawn mower—it's a quick, easy fix.…

Repair difficulty
Time required
 15 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.…