Professional Series™ (Single Cylinder)

World-class performance – time after time. With commercial-grade power, easy starting and quiet operation, the Professional Series riding mower engine delivers great results for your toughest jobs. And it keeps delivering, because this mower engine is built to last with our exclusive Advanced Debris Management System, chrome-plated exhaust valves and other durable features.

15.5 - 20

Gross Horsepower

500 - 656

Displacement (cc)

1.4 - 1.9

Oil Capacity (L)

2 Year

Warranty

Features

Professional Series™ rider mower engines

Single cylinder and V-twin engines offer the best of both worlds: world-class endurance and power.

Advanced Debris Management System

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

Anti-Vibration System - AVS®

Provides a smoother ride and more comfort.

ReadyStart® Engine Starting System

No prime, no choke, no worries. Just pull for power.

Specifications

Only 2 products can be compared at once. Please remove one of your selections to compare this product.

Only 3 products can be compared at once. Please remove one of your selections to compare this product.

At least one product must be displayed. Please select another option to remove this product

Model Number
31S7
Gross Power HP* (kW) @3'600 rpm
15.5.0
Cylinder
Cast Iron Sleeve
Stroke (mm)
77.8
Weight (kg)
29.5
Width (mm)
411
Consumer Limited Warranty†
2 Year
Engine Series
Professional Series™ (Single Cylinder)
Engine Type
Single cylinder, 4-stroke, air cooled, OHV (Overhead Valve)
Engine Displacement (cc)
500
Bore (mm)
90.5
Oil Capacity (L)
1.4
Length (mm)
479
Height (mm)
327
Commercial Limited Warranty†
1 Year
Model Number
31S8
Gross Power HP* (kW) @3'600 rpm
16.5.0
Cylinder
Cast Iron Sleeve
Stroke (mm)
77.8
Weight (kg)
29.5
Width (mm)
411
Consumer Limited Warranty†
2 Year
Engine Series
Professional Series™ (Single Cylinder)
Engine Type
Single cylinder, 4-stroke, air cooled, OHV (Overhead Valve)
Engine Displacement (cc)
500
Bore (mm)
90.5
Oil Capacity (L)
1.4
Length (mm)
479
Height (mm)
327
Commercial Limited Warranty†
1 Year
Model Number
31S9
Gross Power HP* (kW) @3'600 rpm
17.5.0
Cylinder
Cast Iron Sleeve
Stroke (mm)
77.8
Weight (kg)
29.5
Width (mm)
411
Consumer Limited Warranty†
2 Year
Engine Series
Professional Series™ (Single Cylinder)
Engine Type
Single cylinder, 4-stroke, air cooled, OHV (Overhead Valve)
Engine Displacement (cc)
500
Bore (mm)
90.5
Oil Capacity (L)
1.4
Length (mm)
479
Height (mm)
327
Commercial Limited Warranty†
1 Year
Model Number
33S7
Gross Power HP* (kW) @3'600 rpm
18.5.0
Cylinder
Cast Iron Sleeve
Stroke (mm)
77.8
Weight (kg)
29.5
Width (mm)
411
Consumer Limited Warranty†
2 Year
Engine Series
Professional Series™ (Single Cylinder)
Engine Type
Single cylinder, 4-stroke, air cooled, OHV (Overhead Valve)
Engine Displacement (cc)
540
Bore (mm)
94
Oil Capacity (L)
1.4
Length (mm)
479
Height (mm)
327
Commercial Limited Warranty†
1 Year
Model Number
33S8
Gross Power HP* (kW) @3'600 rpm
19.0
Cylinder
Cast Iron Sleeve
Stroke (mm)
77.8
Weight (kg)
29.5
Width (mm)
411
Consumer Limited Warranty†
2 Year
Engine Series
Professional Series™ (Single Cylinder)
Engine Type
Single cylinder, 4-stroke, air cooled, OHV (Overhead Valve)
Engine Displacement (cc)
540
Bore (mm)
94
Oil Capacity (L)
1.4
Length (mm)
479
Height (mm)
327
Commercial Limited Warranty†
1 Year
Model Number
40U7
Gross Power HP* (kW) @3'600 rpm
18.0
Cylinder
Cast Iron Sleeve
Stroke (mm)
73.4
Weight (kg)
37.9
Width (mm)
393
Consumer Limited Warranty†
2 Year
Engine Series
Professional Series™ (Single Cylinder)
Engine Type
V-Twin, 4-stroke, air cooled, OHV (Overhead Valve)
Engine Displacement (cc)
656
Bore (mm)
79.2
Oil Capacity (L)
1.9
Length (mm)
479
Height (mm)
327
Commercial Limited Warranty†
1 Year
Model Number
40U8
Gross Power HP* (kW) @3'600 rpm
20.0
Cylinder
Cast Iron Sleeve
Stroke (mm)
73.4
Weight (kg)
37.6
Width (mm)
393
Consumer Limited Warranty†
2 Year
Engine Series
Professional Series™ (Single Cylinder)
Engine Type
V-Twin, 4-stroke, air cooled, OHV (Overhead Valve)
Engine Displacement (cc)
656
Bore (mm)
79.2
Oil Capacity (L)
1.9
Length (mm)
479
Height (mm)
327
Commercial Limited Warranty†
1 Year

*Power levels are stated gross horsepower at 3600rpm per SAE J1940 as rated by Briggs & Stratton.
†See briggsandstratton.com for warranty details.

Model Number
31S8
31S7
31S8
Engine Type
Single cylinder, 4-stroke, air cooled, OHV (Overhead Valve)
Single cylinder, 4-stroke, air cooled, OHV (Overhead Valve)
Single cylinder, 4-stroke, air cooled, OHV (Overhead Valve)
Gross Power HP* (kW) @3'600 rpm
16.5.0
15.5.0
16.5.0
Engine Displacement (cc)
500
500
500
Cylinder
Cast Iron Sleeve
Cast Iron Sleeve
Cast Iron Sleeve
Bore (mm)
90.5
90.5
90.5
Stroke (mm)
77.8
77.8
77.8
Oil Capacity (L)
1.4
1.4
1.4
Weight (kg)
29.5
29.5
29.5
Length (mm)
479
479
479
Width (mm)
411
411
411
Height (mm)
327
327
327
Consumer Limited Warranty†
2 Year
2 Year
2 Year
Commercial Limited Warranty†
1 Year
1 Year
1 Year
Engine Series
Professional Series™ (Single Cylinder)
Professional Series™ (Single Cylinder)
Professional Series™ (Single Cylinder)

*Power levels are stated gross horsepower at 3600rpm per SAE J1940 as rated by Briggs & Stratton.
†See briggsandstratton.com for warranty details.