Can’t find your part?   Contact us:
+1-309-603-4777
Sears Parts Direct
Tips to find your model number
Orders

  • Keep track of the models you own in your profile

    Sign in or Register to view or add models

Schedule a repair
MTD
Lawn & Garden Engine

Model # 8Q78HU Official MTD engine

Here are the diagrams and repair parts for Official MTD 8Q78HU engine, as well as links to manuals and error code tables, if available.

There are a couple of ways to find the part or diagram you need:

  • Click a diagram to see the parts shown on that diagram.
  • In the search box below, enter all or part of the part number or the part’s name.

Not all parts are shown on the diagrams—those parts are labeled NI, for “not illustrated”.

We encourage you to save the model to your profile, so it’s easy to access parts and manuals for your appliance whenever you log in.

For DIY troubleshooting advice and repair guides, visit our repair help section.

Owner’s manual

Model diagram and schematic

SEARCH WITHIN THIS MODEL

?

This is the number corresponding to the part on the diagram / schematic

Search
ALL PARTS
Showing 10 of 180 parts  |
Lawn & Garden Equipment Engine Spark Plug 951-10292
#8

Cylinder head diagram

Lawn & garden equipment engine spark plug

Part #951-10292

Replaced by #951-10292A

?
Manufacturer substitution
This part replaces 951-10292. Substitute parts can look different from the original.
BEST SELLER
This item is not returnable
$5.70 | 
15% OFF Phone Price : $6.70
In Stock
Lawn & Garden Equipment Engine Nut 712-05015
#20

Crankcase diagram

Lawn & garden equipment engine nut

Part #712-05015

This item is not returnable
$10.14 | 
16% OFF Phone Price : $12.14
In Stock
Lawn & Garden Equipment Engine Mounting Screw 710-04915
Lawn & garden equipment engine mounting screw

Part #710-04915

This item is not returnable
$6.75 | 
13% OFF Phone Price : $7.75
In Stock
Shrd:engine 951-12205
#2

Engine shroud diagram

Shrd:engine

Part #951-12205

$14.37
In Stock
Kmart Lawn & Garden Equipment Bolt 710-04914
Kmart lawn & garden equipment bolt

Part #710-04914

This item is not returnable
$7.37
In Stock
Lawn & Garden Equipment Engine Carburetor Mounting Stud 710-04910
#8

Carburetor accessories diagram

Lawn & garden equipment engine carburetor mounting stud

Part #710-04910

This item is not returnable
$10.91
In Stock
Cap 951-12081
#7

Cylinder head diagram

Cap

Part #951-12081

Replaced by #951-12269

?
Manufacturer substitution
This part replaces 951-12081. Substitute parts can look different from the original.
This item is not returnable
$9.65 | 
9% OFF Phone Price : $10.65
In Stock
Mtd Drain Bolt 910-06752
#6

Carburetor diagram

Mtd drain bolt

Part #910-06752

$8.80
In Stock
Pin-dowel 915-05026
#2

Starter diagram

Pin-dowel

Part #915-05026

$8.69
In Stock
Mtd Governor Spring 932-05617
#12

Carburetor accessories diagram

Mtd governor spring

Part #932-05617

$11.20
In Stock

Repair guides for front-engine lawn tractors

How to replace a ground drive belt on a riding lawn mower

How to replace a ground drive belt on a riding lawn mower

Replace the ground drive belt if it's broken or too worn to spin the transaxle pulley.…

Read more
Repair difficulty
Time required
 45 minutes or less
How to replace a blade clutch cable on a riding lawn mower

How to replace a blade clutch cable on a riding lawn mower

If the blades don't spin on your riding mower when you shift the lever, the blade clutch cable could be broken. Here’s h…

Read more
Repair difficulty
Time required
 30 minutes or less
How to replace a riding lawn mower blade drive belt

How to replace a riding lawn mower blade drive belt

Replace the blade drive belt if it's broken or won't spin the cutting blades because of wear.…

Read more
Repair difficulty
Time required
 45 minutes or less

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

View all
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.…

Read more
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.…

Read more

Parts & More