DOHC Performance and Lean Burn Efficiency at 40 HP
The Suzuki DF40A is a 941 cc three-cylinder four-stroke outboard rated at 40 hp across a 5000-6000 rpm full-throttle operating range, the entry point to Suzuki’s Mid Size line, which runs from 40 to 90 hp. It is the only engine in the 40, 50 and 60 hp class to offer a DOHC powerhead. Suzuki builds it around a set of named technologies: the DOHC 12-valve powerhead, Lean Burn Control, multi-point sequential electronic fuel injection, the Easy Start system, a large-capacity alternator and an anti-corrosion finish.
Powerful and efficient. The 941 cc powerhead carries four valves per cylinder and an air intake system optimized for efficiency in the high rpm range, and Suzuki redesigned components throughout the engine to reduce mechanical loss, including a new oil pump that keeps moving parts better lubricated while using less energy. Suzuki’s Lean Burn Control System monitors engine performance and operating conditions to predict fuel needs and deliver a leaner fuel mixture, improving economy from low speed up into the cruising range. Suzuki’s own testing measured a 23% improvement in fuel consumption over the previous generation on the DF50A, which shares this powerhead.
Easy to live with. Suzuki’s Easy Start System needs one turn of the key; the starter stays engaged until the engine fires. The timing chain is oil-bathed, self-adjusting and maintenance free, and in the 40 to 60 hp class Suzuki’s are the only outboards that use one. A 12 V 19 A alternator produces approximately 11.5 A at just 1000 rpm, enough to keep an assortment of marine electronics running in most situations. The optional Suzuki Troll Mode System adjusts engine speed in 50 rpm increments from idle up to 1200 rpm, from a rocker switch near the helm.
Built for saltwater. Suzuki’s Anti-Corrosion System applies a specially formulated finish directly to the outboard’s aluminum surface, which allows maximum bonding and helps protect the parts that are constantly exposed to saltwater. The DF40A complies with the California Air Resources Board’s (CARB) 3-Star Ultra Low Emission Rating.
- Only DOHC powerhead in the 40, 50 and 60 hp class, 941 cc with four valves per cylinder
- Suzuki Lean Burn Control System for economy from low speed into the cruising range
- Multi-point sequential electronic fuel injection, which Suzuki pioneered in four-stroke outboards
- Maintenance-free oil-bathed timing chain
- 12 V 19 A alternator producing approximately 11.5 A at 1000 rpm
- Optional Suzuki Troll Mode System in 50 rpm steps from idle to 1200 rpm
- Electric start and power trim and tilt standard, 229 lb dry weight
Rigging. The DF40A is rigged to order. Remote-control models come on a 20 in transom; the optional Multi-Function tiller handle is available on a 15 in or 20 in transom, in Pearl Nebular Black only. Every DF40A has electric start and power trim and tilt as standard. Suzuki’s model codes read left to right from the horsepower, with T for power trim and tilt, H for tiller handle, and S, L or X for a 15, 20 or 25 in transom, so a DF40ATL is a 20 in remote model. Contact your Mastry dealer for the right rigging for your transom.
