DF40A

This is the only engine in the 40 hp class to offer DOHC performance, and also the only engine in its class to incorporate a maintenance-free, oil-bathed timing chain, which provides the outboard with increased durability and maintenance free operation. With larger displacements for increased power and performance, Suzuki’s Lean Control System for improved fuel economy and designs that are more compact and lighter in weight than the predecessor, the new DF40A engines also incorporate the Suzuki Troll Mode System.  During the 2011 Miami Boat Show, the Boating Writers of America presented Suzuki Marine with the NMMA Innovation Award for the DF40A/DF50A.

Recommended Transom Height (inches) L: 20
Starting System Electric
Weight LBS L: 229
Engine Type DOHC 12-Valve
Fuel Delivery System Multi Point Sequential Electronic Fuel Injection
No. Of Cylinders 3
Piston Displacement inches (cc) 57.4 (941)
Bore X Stroke Inches (mm) 2.85 x 2.99 (72.5 x 76)
Maximum Output HP 40
Operating Range (RPM) 5000 – 6000
Steering Remote (Tiller Kit Optional)
Choke N/A
Oil Pan Capacity quarts (liter) 2.9 (2.7)
Ignition System Solid State Direct Ignition
Alternator 12V 19A
Trim Position Power Trim and Tilt
Gear Ratio 2.27:1
Standard Propeller Optional See Dealer
Propeller Selection 9 – 17
  • Multi Point Sequential Electronic Fuel Injection
  • Suzuki Lean burn Control System
  • Suzuki Troll Mode System
  • Direct Ignition
  • Suzuki Easy Start System
  • Over-Rev. Limiter
  • Low Oil Pressure Caution
  • Fully Transistorized Ignition
  • Timing Chain
  • Fresh Water Flushing System
  • Power Trim and Tilt
  • Suzuki Anti-Corrosion System

Advantages

Model Name: DF40A Honda 40 Mercury 40 Yamaha 40
Manufacturer: Suzuki Honda Mercury Yamaha
Horsepower: 40 40 (1) 40, (2) 40 EFI, (3) 40 Bigfoot EFI 40
Shaft Length (Inches): L (20) L (20) (1, 2) S15, L20, (3) L20, X25 L 20
Weight (Lbs): 229 L (214) (1) 204, (2) 216, (3) 260 216
Cylinders: In-line 3 In-Line 3 (1, 2) In-Line 3 SOHC, (3) In-Line 4 In-line 3
Valves Per Cylinder: DOHC 4 Valves Per Cyl. SOHC 2 Valves Per Cyl. SOHC 2 Valves Per Cyl. SOHC 2 Valves Per Cyl.
Valve Train Drive: Self adjusting oil bathed timing chain Single overhead belt Single overhead belt Single overhead belt
Displacement: 57.4 cu. in. (941 cc) 49.3 cu. in. (808 cc) (1, 2) 45.6 cu. in. (747 cc), (3) 61 cu. in. (995 cc) 45.6 cu. in. (747 cc.)
Bore and Stroke (Inches/mm): 2.85 x 2.99 in. (72.5 x 76 mm) 2.80 x 2.80 in. (70 x 70 mm) (1,2,3) 2.56 x 2.95 in. (65 x 75 mm) 2.56 x 2.95 in. (65 x 75 mm)
Operating Range (RPM): 5000-6000 5000 – 6000 5500 – 6000 5000 – 6000
Induction System: Sequential EFI with Lean Burn Control Programmed EFI with Lean Burn Control (1) 3 carbs, (2,3) EFI EFI
Starting System: Suzuki Easy Start System Electric (1) Manual w/ Decompression, (2, 3) Electric Electric or Manual
Lubrication: Wet sump Wet sump Wet sump Wet sump
Oil Tank Capacity: 2.9 qt. (2.7 lit.) 2.5 qt. (2.4 lit.) 2.3 qt. (2.2 lit.) 2.1 qt. (2.0 lit.)
Ignition: Direct Ignition CDI* (1) CDI, (2, 3) Digital Inductive CDI Micro Computer
Alternator: 12V 19A 22 A (1) 6 A, (2,3) 18 A 16 A
Trim Type: Power Trim and Tilt Power Tilt Power Trim and Tilt, Gas Assist Power Trim and Tilt
Gear Ratio: 2.27:1 2.08:1 (1, 2) 2.00:1, (3) 2.33:1 2.00:1/13:26
CARB Emissions Rating: 3-Star Ultra-Low 3-Star Ultra-Low 3-Star Ultra-Low 3-Star Ultra-Low
Standard Propeller (Blades x Dia. x Pitches (Ins.)): Optional – See Dealer N/A N/A N/A
Range of Avail. Optional Propeller Pitches: 9 – 17 Unknown 8 – 19 Unknown
Steering: Remote (Tiller Kit optional) Unknown Unknown Unknown

DF40A Advantages

Over Honda
  • Larger Displacement 941cc (57.4 c.i.) vs. 808cc (49.2 c.i.) No replacement for displacement
  • Zero Maintenance Self Adjusting Timing Chain vs. Inspect and Replace Timing Belt
  • 2.27:1 vs. 2.00:1 Lower gear ratio to swing a larger prop for improved acceleration
  • Suzuki Easy Start System for customer convenience
Over Mercury
  • Suzuki Lean Burn Control System – Improved fuel economy
  • Zero Maintenance Self Adjusting Timing Chain vs. Inspect and Replace Timing Belt
  • DOHC 4 valves per cylinder vs. SOHC 2 valves per cylinder
  • Larger Displacement 941cc (57.4 c.i.) vs. 747cc (45.6 c.i.) No replacement for displacement
  • 2.27:1 vs. 2.00:1 Lower gear ratio to swing a larger prop for improved acceleration
  • Direct Ignition vs. standard coil for reduce electrical interference
  • Suzuki Easy Start System for customer convenience
Over Yamaha
  • Suzuki Lean Burn Control System – Improved fuel economy
  • Zero Maintenance Self Adjusting Timing Chain vs. Inspect and Replace Timing Belt
  • DOHC 4 valves per cylinder vs. SOHC 2 valves per cylinder
  • Larger Displacement 941cc (57.4 c.i.) vs. 747cc (45.6 c.i.) No replacement for displacement
  • 2.27:1 vs. 2.00:1 Lower gear ratio to swing a larger prop for improved acceleration
  • Direct Ignition vs. standard coil for reduce electrical interference
  • Suzuki Easy Start System for customer convenience