This spring you’ll see a hot new outboard churning the waters, the all-new F350 from Yamaha. This 4.3L V6 powerplant is based on the epically reliable and battle-hardened 4.2L V6, but has many of the features pioneered on Yamaha’s XTO offshore models. And gaining just 18 pounds as compared to the 4.2L F300, the 629-pound F350 has the highest power-to-weight ratio in its class.
The added displacement and extra horsepower come from an extended stroke, a higher compression ratio (11:1) and improved airflow. The new electronic throttle valve is eight percent larger and the intake air moves through surge tanks which have been expanded by 40 percent. Additional upgrades include a newly designed crankshaft built from an improved steel alloy, carbon-coated valve lifters, an integrated flywheel fan, and a move to iridium spark plugs. The F350 also boasts a new lower unit, which has the same footprint as older units but additional teeth in the clutch dog.
As one would expect the F350 gets a full dose of tech from Yamaha’s usual playbook, too: cylinders are plasma-fused to eliminate the need for sleeves while evening out heat distribution and reducing friction; exhaust gasses are evacuated above the anti-ventilation plate when operating in reverse to prevent gasses from hitting the prop and reducing its bite; digital electronic steering comes standard, and complete integration with Helm Master EX and joystick steering is available.
We ran the F350 on a couple of boats at the Miami International Boat Show last February, and found them to perform exactly as expected. Like the other 4.2L engines in the Yamaha lineup the F350 idles in near-silence, and remains quiet and low in vibration through the newly extended powerband. On a World Cat 325 CC they produced a cruise of around 40 mph while getting 1.3 mpg and a top-end of close to 58 mph. Compare that to a previous World Cat 325 test with F300s, which resulted in a cruise of about three mph less while also getting 0.2 fewer mpg, and a top-end just under 50.
By the time you read this the F350 will be found on transoms throughout the Bay and along the coast; check out our Chesapeake Bay and Mid-Atlantic Yamaha Outboard Dealers page for more intel.