EX Series™ Engines

EX Series™ Engines

Efficient and durable performance.

With more power and features, our EX Series riding mower engines give you the performance you need. The lubrication system extends engine life, and includes a standard oil filter and oil pump to push clean oil to critical components. Superior air filtering and reduced vibration come standard. Make starting easier – just like a car – with our optional no choke technology.

344 - 540cc

Displacement

Gas

Engine Fuel

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
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)
Oil Capacity (oz)
48
Lubrication System
Partial Lubrication System
Oil Filter
Standard
Starter
Electric Start, Recoil Optional
Air Filter
Cartridge Air Cleaner with Advanced Debris Management
Muffler
Optional
Fuel Shutoff Valve
Optional
Certified Power Rating
Marketing Oil Capacity
48
Marketing Number of Cylinders
1
Marketing Gross Horsepower
10.5 - 19.0
Gross Horsepower
10.5

*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)
Oil Capacity (oz)
48
Lubrication System
Partial Lubrication System
Oil Filter
Standard
Starter
Electric Start, Recoil Optional
Air Filter
Cartridge Air Cleaner with Advanced Debris Management
Muffler
Optional
Fuel Shutoff Valve
Optional
Certified Power Rating
Marketing Oil Capacity
48
Marketing Number of Cylinders
1
Marketing Gross Horsepower
10.5 - 19.0
Gross Horsepower
11.5

*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
Oil Capacity (oz)
48
Lubrication System
Partial Lubrication System
Oil Filter
Standard
Starter
Electric Start
Air Filter
Cartridge Air Cleaner with Advanced Debris Management
Muffler
Optional
Fuel Shutoff Valve
Optional
Certified Power Rating
Marketing Oil Capacity
48
Marketing Number of Cylinders
1
Marketing Gross Horsepower
10.5 - 19.0
Gross Horsepower
13.5

*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
Oil Capacity (oz)
48
Lubrication System
Partial Lubrication System
Oil Filter
Standard
Starter
Electric Start
Air Filter
Cartridge Air Cleaner with Advanced Debris Management
Muffler
Optional
Fuel Shutoff Valve
Optional
Certified Power Rating
Marketing Oil Capacity
48
Marketing Number of Cylinders
1
Marketing Gross Horsepower
10.5 - 19.0
Gross Horsepower
14.5

*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
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
Oil Capacity (oz)
48
Lubrication System
Partial Lubrication System
Oil Filter
Premium
Starter
Electric Start
Air Filter
Dual Element Cartridge with Advanced Debris Management
Muffler
Optional
Fuel Shutoff Valve
Optional
Certified Power Rating
Marketing Oil Capacity
48
Marketing Number of Cylinders
1
Marketing Gross Horsepower
10.5 - 19.0
Gross Horsepower
15.5

*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
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
Oil Capacity (oz)
48
Lubrication System
Partial Lubrication System
Oil Filter
Premium
Starter
Electric Start
Air Filter
Dual Element Cartridge with Advanced Debris Management
Muffler
Optional
Fuel Shutoff Valve
Optional
Certified Power Rating
Marketing Oil Capacity
48
Marketing Number of Cylinders
1
Marketing Gross Horsepower
10.5 - 19.0
Gross Horsepower
16.5

*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
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
Oil Capacity (oz)
48
Lubrication System
Partial Lubrication System
Oil Filter
Premium
Starter
Electric Start
Air Filter
Dual Element Cartridge with Advanced Debris Management
Muffler
Optional
Fuel Shutoff Valve
Optional
Certified Power Rating
Marketing Oil Capacity
48
Marketing Number of Cylinders
1
Marketing Gross Horsepower
10.5 - 19.0
Gross Horsepower
17.5

*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
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
Oil Capacity (oz)
48
Lubrication System
Partial Lubrication System
Oil Filter
Standard
Starter
Electric Start
Air Filter
Cartridge Air Cleaner with Advanced Debris Management
Muffler
Optional
Fuel Shutoff Valve
Optional
Certified Power Rating
Marketing Oil Capacity
48
Marketing Number of Cylinders
1
Marketing Gross Horsepower
10.5 - 19.0
Gross Horsepower
18.5

*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
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
Oil Capacity (oz)
48
Lubrication System
Full Pressure Lubrication
Oil Filter
Premium
Starter
Electric Start
Air Filter
Dual Element Cartridge with Advanced Debris Management
Muffler
Optional
Fuel Shutoff Valve
Optional
Certified Power Rating
Marketing Oil Capacity
48
Marketing Number of Cylinders
1
Marketing Gross Horsepower
10.5 - 19.0
Gross Horsepower
19

*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
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
Oil Capacity (oz)
48
48
48
48
48
48
48
48
48
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 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
Marketing Oil Capacity
48
48
48
48
48
48
48
48
48
Marketing Number of Cylinders
1
1
1
1
1
1
1
1
1
Marketing Gross Horsepower
10.5 - 19.0
10.5 - 19.0
10.5 - 19.0
10.5 - 19.0
10.5 - 19.0
10.5 - 19.0
10.5 - 19.0
10.5 - 19.0
10.5 - 19.0
Gross Horsepower
10.5
11.5
13.5
14.5
15.5
16.5
17.5
18.5
19
Torque (ft-lbs, gross)*
11.5
13.5
14.5

*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.

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