EX Series™ Engines

EX Series™ Engines

Efficient and durable performance.

With more power & features, our EX Series™ riding mower engines give you the performance and value you need. Our full pressure lubrication system offers a premium oil filter and the oil is now also being pushed into the crank pin bearing for extended durability and longer life. Equipped with ReadyStart® starting technology, there's no choke - like automotive-style starting, you just turn the key or push a button and go!

  • Advanced Debris Managment System - Helps our engines run cleaner and longer by deflecting and ejecting grass and debris, providing a longer life.
  • Anti-Vibration System® (AVS) - Gives you a smoother ride, saving wear and tear on your engine, your equipment and you.
  • Chrome-plated Exhaust and Super Finished Crankshaft - helps to reduce friction and minimize wear for additional extended life.
  • Made in the USA - Made of US and global parts; manufactured in the US.

10.5 - 19.0

Gross Torque (ft-lbs)

344 - 540cc

Displacement

Gasoline

Engine Fuel

48

Oil Capacity (oz)

Features

Made in the USA

Made in the USA of US and global parts.

ReadyStart® for Ride Technology

Automotive-style, no choke easy starting. Just turn the key or push the button and go.

Anti-Vibration System - AVS®

Provides a smoother ride and more comfort.

Advanced Debris Management System

Keeps the engine clean by deflecting and ejecting grass and debris for a longer engine life.

Full Pressure Lube System

Reduces component wear for longer engine life.

Specs

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Model Number
21R7
Torque (ft-lbs, gross)*
10.5
Engine Displacement (cc)
344
Number of Cylinders
Single
Engine Configuration
Vertical Shaft
OHV Engine
Yes
Length (in)
17.8
Width (in)
15.5
Height (in)
12.9
Weight (lbs)
66
Bore (in)
3.44
Stroke (in)
2.26
Engine Fuel
Gasoline
Fuel Tank Capacity (gal)
0.7 (optional)
Lubrication System
Partial Lubrication System
Oil Capacity (oz)
48
Oil Filter
Standard
Starter
Electric Start, Recoil Optional
Air Filter
Cartridge Air Cleaner with Advanced Debris Management
Muffler
Optional
Certified Power Rating
Fuel Shutoff Valve
Optional

*All power levels are stated gross torque at 2600 rpm per SAE J1940 as rated by Briggs & Stratton.
**All power levels are stated gross horsepower at 3600 rpm per SAE J1940 as rated by Briggs & Stratton.

Model Number
21R8
Torque (ft-lbs, gross)*
11.5
Engine Displacement (cc)
344
Number of Cylinders
Single
Engine Configuration
Vertical Shaft
OHV Engine
Yes
Length (in)
17.8
Width (in)
15.5
Height (in)
12.9
Weight (lbs)
66
Bore (in)
3.44
Stroke (in)
2.26
Engine Fuel
Gasoline
Fuel Tank Capacity (gal)
0.7 (optional)
Lubrication System
Partial Lubrication System
Oil Capacity (oz)
48
Oil Filter
Standard
Starter
Electric Start, Recoil Optional
Air Filter
Cartridge Air Cleaner with Advanced Debris Management
Muffler
Optional
Certified Power Rating
Fuel Shutoff Valve
Optional

*All power levels are stated gross torque at 2600 rpm per SAE J1940 as rated by Briggs & Stratton.
**All power levels are stated gross horsepower at 3600 rpm per SAE J1940 as rated by Briggs & Stratton.

Model Number
31R5
Torque (ft-lbs, gross)*
13.5
Engine Displacement (cc)
500
Number of Cylinders
Single
Engine Configuration
Vertical Shaft
OHV Engine
Yes
Length (in)
18.9
Width (in)
15.5
Height (in)
12.9
Weight (lbs)
77
Bore (in)
3.56
Stroke (in)
3.06
Engine Fuel
Gasoline
Fuel Tank Capacity (gal)
N/A
Lubrication System
Partial Lubrication System
Oil Capacity (oz)
48
Oil Filter
Standard
Starter
Electric Start
Air Filter
Cartridge Air Cleaner with Advanced Debris Management
Muffler
Optional
Certified Power Rating
Fuel Shutoff Valve
Optional

*All power levels are stated gross torque at 2600 rpm per SAE J1940 as rated by Briggs & Stratton.
**All power levels are stated gross horsepower at 3600 rpm per SAE J1940 as rated by Briggs & Stratton.

Model Number
31R6
Torque (ft-lbs, gross)*
14.5
Engine Displacement (cc)
500
Number of Cylinders
Single
Engine Configuration
Vertical Shaft
OHV Engine
Yes
Length (in)
18.9
Width (in)
15.5
Height (in)
12.9
Weight (lbs)
77
Bore (in)
3.56
Stroke (in)
3.06
Engine Fuel
Gasoline
Fuel Tank Capacity (gal)
N/A
Lubrication System
Partial Lubrication System
Oil Capacity (oz)
48
Oil Filter
Standard
Starter
Electric Start
Air Filter
Cartridge Air Cleaner with Advanced Debris Management
Muffler
Optional
Certified Power Rating
Fuel Shutoff Valve
Optional

*All power levels are stated gross torque at 2600 rpm per SAE J1940 as rated by Briggs & Stratton.
**All power levels are stated gross horsepower at 3600 rpm per SAE J1940 as rated by Briggs & Stratton.

Model Number
31R7
Torque (ft-lbs, gross)*
15.5
Engine Displacement (cc)
500
Number of Cylinders
Single
Engine Configuration
Vertical Shaft
OHV Engine
Yes
Length (in)
18.9
Width (in)
15.5
Height (in)
12.9
Weight (lbs)
77
Bore (in)
3.56
Stroke (in)
3.06
Engine Fuel
Gasoline
Fuel Tank Capacity (gal)
N/A
Lubrication System
Partial Lubrication System
Oil Capacity (oz)
48
Oil Filter
Premium
Starter
Electric Start
Air Filter
Dual Element Cartridge with Advanced Debris Management
Muffler
Optional
Certified Power Rating
Fuel Shutoff Valve
Optional

*All power levels are stated gross torque at 2600 rpm per SAE J1940 as rated by Briggs & Stratton.
**All power levels are stated gross horsepower at 3600 rpm per SAE J1940 as rated by Briggs & Stratton.

Model Number
31R8
Torque (ft-lbs, gross)*
16.5
Engine Displacement (cc)
500
Number of Cylinders
Single
Engine Configuration
Vertical Shaft
OHV Engine
Yes
Length (in)
18.9
Width (in)
15.5
Height (in)
12.9
Weight (lbs)
77
Bore (in)
3.56
Stroke (in)
3.06
Engine Fuel
Gasoline
Fuel Tank Capacity (gal)
N/A
Lubrication System
Partial Lubrication System
Oil Capacity (oz)
48
Oil Filter
Premium
Starter
Electric Start
Air Filter
Dual Element Cartridge with Advanced Debris Management
Muffler
Optional
Certified Power Rating
Fuel Shutoff Valve
Optional

*All power levels are stated gross torque at 2600 rpm per SAE J1940 as rated by Briggs & Stratton.
**All power levels are stated gross horsepower at 3600 rpm per SAE J1940 as rated by Briggs & Stratton.

Model Number
31R9
Torque (ft-lbs, gross)*
17.5
Engine Displacement (cc)
500
Number of Cylinders
Single
Engine Configuration
Vertical Shaft
OHV Engine
Yes
Length (in)
18.9
Width (in)
15.5
Height (in)
12.9
Weight (lbs)
77
Bore (in)
3.56
Stroke (in)
3.06
Engine Fuel
Gasoline
Fuel Tank Capacity (gal)
N/A
Lubrication System
Partial Lubrication System
Oil Capacity (oz)
48
Oil Filter
Premium
Starter
Electric Start
Air Filter
Dual Element Cartridge with Advanced Debris Management
Muffler
Optional
Certified Power Rating
Fuel Shutoff Valve
Optional

*All power levels are stated gross torque at 2600 rpm per SAE J1940 as rated by Briggs & Stratton.
**All power levels are stated gross horsepower at 3600 rpm per SAE J1940 as rated by Briggs & Stratton.

Model Number
33R7
Torque (ft-lbs, gross)*
18.5
Engine Displacement (cc)
540
Number of Cylinders
Single
Engine Configuration
Vertical Shaft
OHV Engine
Yes
Length (in)
18.9
Width (in)
16.2
Height (in)
12.9
Weight (lbs)
77
Bore (in)
3.70
Stroke (in)
3.06
Engine Fuel
Gasoline
Fuel Tank Capacity (gal)
N/A
Lubrication System
Partial Lubrication System
Oil Capacity (oz)
48
Oil Filter
Standard
Starter
Electric Start
Air Filter
Cartridge Air Cleaner with Advanced Debris Management
Muffler
Optional
Certified Power Rating
Fuel Shutoff Valve
Optional

*All power levels are stated gross torque at 2600 rpm per SAE J1940 as rated by Briggs & Stratton.
**All power levels are stated gross horsepower at 3600 rpm per SAE J1940 as rated by Briggs & Stratton.

Model Number
33R8
Torque (ft-lbs, gross)*
19
Engine Displacement (cc)
540
Number of Cylinders
Single
Engine Configuration
Vertical Shaft
OHV Engine
Yes
Length (in)
18.9
Width (in)
16.2
Height (in)
12.9
Weight (lbs)
77
Bore (in)
3.70
Stroke (in)
3.06
Engine Fuel
Gasoline
Fuel Tank Capacity (gal)
N/A
Lubrication System
Full Pressure Lubrication
Oil Capacity (oz)
48
Oil Filter
Premium
Starter
Electric Start
Air Filter
Dual Element Cartridge with Advanced Debris Management
Muffler
Optional
Certified Power Rating
Fuel Shutoff Valve
Optional

*All power levels are stated gross torque at 2600 rpm per SAE J1940 as rated by Briggs & Stratton.
**All power levels are stated gross horsepower at 3600 rpm per SAE J1940 as rated by Briggs & Stratton.

Model Number
21R7
21R8
31R5
31R6
31R7
31R8
31R9
33R7
33R8
Torque (ft-lbs, gross)*
10.5
11.5
13.5
14.5
15.5
16.5
17.5
18.5
19
Engine Displacement (cc)
344
344
500
500
500
500
500
540
540
Number of Cylinders
Single
Single
Single
Single
Single
Single
Single
Single
Single
Engine Configuration
Vertical Shaft
Vertical Shaft
Vertical Shaft
Vertical Shaft
Vertical Shaft
Vertical Shaft
Vertical Shaft
Vertical Shaft
Vertical Shaft
OHV Engine
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Length (in)
17.8
17.8
18.9
18.9
18.9
18.9
18.9
18.9
18.9
Width (in)
15.5
15.5
15.5
15.5
15.5
15.5
15.5
16.2
16.2
Height (in)
12.9
12.9
12.9
12.9
12.9
12.9
12.9
12.9
12.9
Weight (lbs)
66
66
77
77
77
77
77
77
77
Bore (in)
3.44
3.44
3.56
3.56
3.56
3.56
3.56
3.70
3.70
Stroke (in)
2.26
2.26
3.06
3.06
3.06
3.06
3.06
3.06
3.06
Engine Fuel
Gasoline
Gasoline
Gasoline
Gasoline
Gasoline
Gasoline
Gasoline
Gasoline
Gasoline
Fuel Tank Capacity (gal)
0.7 (optional)
0.7 (optional)
N/A
N/A
N/A
N/A
N/A
N/A
N/A
Lubrication System
Partial Lubrication System
Partial Lubrication System
Partial Lubrication System
Partial Lubrication System
Partial Lubrication System
Partial Lubrication System
Partial Lubrication System
Partial Lubrication System
Full Pressure Lubrication
Oil Capacity (oz)
48
48
48
48
48
48
48
48
48
Oil Filter
Standard
Standard
Standard
Standard
Premium
Premium
Premium
Standard
Premium
Starter
Electric Start, Recoil Optional
Electric Start, Recoil Optional
Electric Start
Electric Start
Electric Start
Electric Start
Electric Start
Electric Start
Electric Start
Air Filter
Cartridge Air Cleaner with Advanced Debris Management
Cartridge Air Cleaner with Advanced Debris Management
Cartridge Air Cleaner with Advanced Debris Management
Cartridge Air Cleaner with Advanced Debris Management
Dual Element Cartridge with Advanced Debris Management
Dual Element Cartridge with Advanced Debris Management
Dual Element Cartridge with Advanced Debris Management
Cartridge Air Cleaner with Advanced Debris Management
Dual Element Cartridge with Advanced Debris Management
Muffler
Optional
Optional
Optional
Optional
Optional
Optional
Optional
Optional
Optional
Fuel Shutoff Valve
Optional
Optional
Optional
Optional
Optional
Optional
Optional
Optional
Optional

*All power levels are stated gross torque at 2600 rpm per SAE J1940 as rated by Briggs & Stratton.
**All power levels are stated gross horsepower at 3600 rpm per SAE J1940 as rated by Briggs & Stratton.

Support

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