To paraphrase an old expression, what’s something old, something new, something borrowed that you’d like to take to the blue (water)? The easy answer is Yamaha’s new F350 V-6 four stroke outboard, which made its big league debut at the recent 2024 Miami International Boat Show.
Ever since Yamaha retired their 350 V-8 outboard a few years back, there’s been a huge hole in their offshore lineup between the popular F300 V-6 and the supersized F450 XTO V-8. The design team heard the call and spent the last few years creating the next-gen F350, a 4.3-liter V-6 that externally looks like her F300 sibling, but in actuality has a number of key differences which we’ll detail shortly. As I walked up and down the busy aisles at the Miami Beach Convention Center, there were rows of Yamaha OEM partners like Grady-White, Regulator, Cobia and others sporting either pairs or trips of these new V-6 four-strokes and it came just in time for Yamaha fans and dealers, given the competitive pressures of the marketplace.
High Tech/New Tech
The F350 4.3-liter V6 outboard boasts larger intake and exhaust valves than the F300 and uses the same diameter electronic throttle valve as the 5.6L V8 XTO 450 to maximize air movement. Better air flow translates to more power as the F350’s precisely mapped fuel and ignition timing match operator throttle demand for responsive performance. A new crankshaft offers a longer stroke, enabling more torque at lower speeds. With an 11:1 compression ratio, the new F350 manages air displacement using tailored intake manifolds equipped with 40% larger surge tanks compared to the F300. Larger intake and exhaust valves and Variable Camshaft Timing (VCT) offer improved air flow and the iridium spark plugs combine with Yamaha’s new fuel injection control mapping, which produces a longer injector duration than that of the F300 4.2L for more power. The Yamaha F350 incorporates the same water sensor for overheat control used on the XTO 450, which helps catch increasing engine temps sooner than traditional sensors by monitoring the temperature of the cooling water, not the block. A size-up in oil cooler capacity over the F300, along with Yamaha’s sleeveless, plasma-fused cylinder technology reduce friction and create precise heat distribution.
The F350’s new gearcase is merged with Yamaha’s Thrust Enhancing Reverse Exhaust (TERE) technology, which keeps exhaust bubbles above the anti-ventilation plate and away from the propeller at 2500 RPM in reverse to produce high thrust when backing down on a fish and to add more precision when maneuvering around the docks. The F350 is offered in full model 25-inch or 30-inch shaft lengths and 25-inch, 30-inch and 35-inch for late-stage customized (LSC) lower unit models.
The F350’s cowling features a water-draining air duct while the cowling exhaust port combines with the new stator fan keeps everything under the hood nice and cool. The added cooling effect creates more available current for the F350 over the F300 at all RPMS, especially in the lower RPM ranges. Used in concert with Helm Master EX, Digital Electric Steering (DES) provides clean rigging and extra bilge space that offers smooth, responsive steering and easy maintenance. Borrowing XTO functionality, the F350 has a convenient flush connection running inside the rigging tube that can be connected to an automatic flushing system. Manual flush is also possible via a separate flushing connection. The F350 also incorporates the same TotalTilt technology used throughout Helm Master EX capable DEC outboards.
Sea Trial
I was able to run a SeaPro 322 Offshore that was rigged with a pair of the new F350s down at the Miami show. Racing back and forth in a very crowded and choppy south channel of Government Cut, acceleration was brisk with instantaneous response to the twin electric controls. With all of that extra air getting jammed into this V-6’s combustion chambers, she produces a very distinct growl when hitting the throttles.
Spinning counter rotating 15×20 SWSII three-blade stainless steel props, we were able to hit a top speed in the high-50s at wide open throttle. With a little down tab, I planed this big center console at a sleepy 3,000 rpm, where she hit a solid 20 mph for steady rough water transit. Bumping up the E-throttles, the twin F350s pushed the SeaPro 322 to 29 mph at 17 gph for a net of 1.7 mpg at 3,500 and 35 mph/22 gph/1.6 mpg at four grand; advancing the controls to 4,500 rpm turned 41 mph at 29 gph for a 1.4-mpg bottom line.
Offered in Pearlescent White, Traditional Gray, or new Classic White the new Yamaha F350 will be seen at a marina near you soon.
Visit Yamaha Marine for more information: https://yamahaoutboards.com/outboards/350-150-hp/v6-4-3l
