MTD
Lawn & Garden Engine

Model # 4P90MUA Official MTD engine

Here are the diagrams and repair parts for Official MTD 4P90MUA 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.

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 173 parts  |

Lawn & Garden Equipment Engine Spark Plug 951-10292
#162

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 Oil Filter 951-12690
#114

Crankshaft & crankcase cover diagram

Lawn & garden equipment engine oil filter

Part #951-12690

Replaced by #490-201-Y010

?
Manufacturer substitution
This part replaces 951-12690. Substitute parts can look different from the original.
BEST SELLER
$16.97
11% OFF Phone Price : $18.97
In Stock
Lawn & Garden Equipment Engine Carburetor Gasket 951-12261
#136

Carburetor diagram

Lawn & garden equipment engine carburetor gasket

Part #951-12261

BEST SELLER
This item is not returnable
$6.35
14% OFF Phone Price : $7.35
In Stock
Lawn & Garden Equipment Engine Starter Motor 951-12207
#9

Starter diagram

Lawn & garden equipment engine starter motor

Part #951-12207

Replaced by #751P12207A

?
Manufacturer substitution
This part replaces 951-12207. Substitute parts can look different from the original.
$229.80
5% OFF Phone Price : $241.80
In Stock
Lawn & Garden Equipment Engine Carburetor Float Bowl Gasket 951-11349
#CC

Carburetor diagram

Lawn & garden equipment engine carburetor float bowl gasket

Part #951-11349

Replaced by #951-11349A

?
Manufacturer substitution
This part replaces 951-11349. Substitute parts can look different from the original.
This item is not returnable
$5.64
15% OFF Phone Price : $6.64
In Stock
Lawn Tractor Engine Manifold Gasket 951-12258
#130

Air intake diagram

Lawn tractor engine manifold gasket

Part #951-12258

Replaced by #951-12258A

?
Manufacturer substitution
This part replaces 951-12258. Substitute parts can look different from the original.
This item is not returnable
$6.35
14% OFF Phone Price : $7.35
In Stock
Lawn Tractor Engine Sump Filter 951-12249
#100

Crankshaft & crankcase cover diagram

Lawn tractor engine sump filter

Part #951-12249

This item is not returnable
$6.35
14% OFF Phone Price : $7.35
In Stock
Lawn & Garden Equipment Engine Flywheel Key 951-10307
#77

Crankshaft & crankcase cover diagram

Lawn & garden equipment engine flywheel key

Part #951-10307

Replaced by #751P10307A

?
Manufacturer substitution
This part replaces 951-10307. Substitute parts can look different from the original.
This item is not returnable
$3.22
24% OFF Phone Price : $4.22
In Stock
Lawn & Garden Equipment Engine Oil Seal 951-11375
#118

Crankshaft & crankcase cover diagram

Lawn & garden equipment engine oil seal

Part #951-11375

Replaced by #951-11375A

?
Manufacturer substitution
This part replaces 951-11375. Substitute parts can look different from the original.
In Stock
Lawn & Garden Equipment Engine Exhaust Gasket 951-12271
#160

Muffler diagram

Lawn & garden equipment engine exhaust gasket

Part #951-12271

This item is not returnable
In Stock

Symptoms for gas pressure washers

Choose a symptom to see related pressure washer repairs.

Main causes: using a high-pressure spray tip when applying detergent, clogged siphon tube, chemical injection system fai…

Main causes: overfilling engine with oil, improper fuel/air mixture, choke system problems, dirty carburetor, engine nee…

Main causes: broken recoil spring, damaged recoil starter…

Main causes: dirty air filter, stale fuel, clogged or dirty carburetor, bad unloader valve…

Main causes: insufficient water supply, clogged water inlet screen, clogged pressure hose, faulty pump check valves, stu…

Main causes: damaged recoil starter, oil inside cylinder, locked up engine piston…

Main causes: faulty unloader valve, bad pressure regulator…

Main causes: stale fuel, gummed up carburetor, engine needs tune up, throttle and choke controls need adjustment, bad re…

Main causes: pump running for more than 5 minutes when the spray wand isn't being used, faulty pressure relief valve, ba…

Repair guides for gas pressure washers

These step-by-step repair guides will help you safely fix what’s broken on your pressure washer.

How to install a pressure washer check valve kit

How to install a pressure washer check valve kit

Air in the inlet water supply can damage the check valves. If the pump won’t build up pressure due to damaged check valv…

Repair difficulty
Time required
 120 minutes or less
How to install a pressure washer O-ring kit

How to install a pressure washer O-ring kit

O-rings seal fittings on the pressure washer pump. Damaged seals allow water to leak from the pump. Follow these steps t…

Repair difficulty
Time required
 45 minutes or less
How to install a pressure washer chemical injection kit

How to install a pressure washer chemical injection kit

The chemical injection valve draws detergent into the pump. If it’s not drawing detergent, use a repair kit to replace t…

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 pressure washer.

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.…