Yamaha's biggest V6 engine
Yamaha's new 350hp engine joins the V6 range already comprising 225hp, 250hp and 300hp, closing the gap between the V6 and the 400hp and 450hp XTO V8s. It competes directly with Suzuki, which already has a 350 hp V6. Mercury and Honda also have engines of the same power, but on V10 and V8 blocks respectively.
This engine features larger intake and exhaust valves than the 300 hp V6, and uses an electronic throttle valve of the same diameter as the 450 hp XTO V8 to optimize airflow. This should give it better airflow, and therefore more power, while the new crankshaft will increase high torque at lower speeds.
Compression ratio is 11:1 and boost tanks are 40% larger. The 81 mm electronic throttle valve is also 8% larger than the 300 hp V6's throttle valve. It is axially mounted for smoother airflow and greater responsiveness.
The intake and exhaust valves are also larger. Improved camshaft profile provides higher valve lift, for longer opening times. New valve lifters, made from the same material as those on the XTO 450 hp, improve combustion. The new 350 hp V6 also features iridium spark plugs, combined with Yamaha's new fuel injection mapping, for longer injection times than the 300 hp V6.
Improvements to the Helm Master EX system
The Helm Master EX control system makes maneuvering easier. For 2024, Yamaha builds on the variable-speed bow thruster system integrated into the joystick, to offer new configurations for boats with four to five outboard motors. Yamaha's 704 mechanical control box is now available with a neutral lock, which holds the engine in this position while it is running. This feature allows idling on the water or while waiting near a dock. The control box has been raised for better one-handed throttle control, and better trim adjustment thanks to a thumb-operated toggle knob.
