Yamaha Marine Group today unveiled the boating industry’s first V8 5.3-liter, four-stroke outboard motor, the Yamaha F350. Producing 350 prop-shaft rated horsepower, it is designed to provide massive thrust for the heaviest off-shore outboard-powered boats and outboard-powered boats the industry has, thus far, only been able to dream about building.

“The F350 will allow our boat builder partners to make outboard-powered boats that could reach 40 feet or more in length,” said Phil Dyskow, Yamaha Marine Group president. “At the same time, it’s a great power solution for a lot of existing boats. The F350 will be the choice for anyone who ever wished for more off-shore outboard power and thrust.”

“The development of the F350 was truly an example of Yamaha’s partnership,” said Leon Slikkers, chairman and COO of S2 Yachts (the parent company of Pursuit Boats). “We’ve been working together on the idea of the F350 for several years. It’s great to know we will have them on the transom soon.”

Read and/or comment about the new motor on the FS Forum: http://outdoorsbest.zeroforum.com/zerothread?id=587704

“There are situations in which bigger is truly better,” said Dyskow. “No outboard manufacturer has ever designed anything even close to a 5.3-liter, four-stroke V8. Extra displacement helps provide what big boats need most – thrust. At the same time, displacement means the engine makes 350 horsepower without the strain and internal pressures found in high-output, small displacement engines.

Though the Yamaha brand is already known for offshore reliability, the company has deliberately raised the standard with the F350. For example, it is more resistant to the potential for water intrusion. It also uses a number of new technologies, including: ionic combustion sensors that constantly monitor combustion conditions and adjust spark timing; a dimpled outer cylinder sleeve to reduce oil consumption; the new Enhanced Ultimate Corrosion Protection System (UCP-II™) with additional sacrificial anodes; an innovative internal paint process and new-generation head gaskets; and Yamaha’s Command Link® Digital Electronic Control system with redundant electronic engine control, automatic multi-engine synchronization and electronic throttle and shift.

The Yamaha F350 provides up to 45 percent more thrust than 250-hp class outboards. The company’s first V8 outboard powerhead was designed specifically for the marine market and features more than 600 new parts. The design is a 60-degree V8 with 32 valves (four valves per cylinder) and double overhead cams. It uses variable camshaft timing to optimize the engine’s torque at low and mid-range rpm. With sequential, multi-point fuel injection, it has eight long intake tracks in the induction system to optimize power. In addition, it features In-Bank Exhaust with Dual Power Surge Chambers, a system that relieves pressure in the exhaust ports.

The F350 was designed from the beginning to power off-shore boats. However, it employs a number of new features designed to even further enhance its capabilities. A component of the UCP-II Ultimate Corrosion Protection System is an industry exclusive paint process for the proprietary Yamaha aluminum alloy engine block. It combats corrosion both inside and out, protecting the cooling passages and other key components. In addition, the outboard uses an “Ultra- Tough” gear case with dual water inlets for improved cooling. Inside the lower unit are hardened gears and enhanced bearings and surfaces for greater off-shore durability. Forged motor mounts and an oversized mounting bracket also add to the F350’s portfolio of toughness.

F350 Specifications

Block configuration	V8 60 degree
Displacement	5.3 Liter (5330 cc) (325 ci)
Prop shaft horsepower	350 @ 5500 rpm
Cylinder heads	DOHC / 32 valve with Variable Camshaft Timing (VCT)
Compression	9.6:1
Full Throttle RPM range	5000 – 6000
Fuel induction	Sequential multi-point Electronic Fuel Injection
Fuel type	Regular Unleaded (Minimum Pump Octane 89)
Exhaust	In-bank dual exhaust with Power Surge Chambers
Intake	Electronic throttle valve with 8 individual long intake tracks
Ignition system	32-bit ECM with integrated coil-in-cap ignition design
Alternator Output	50A (40A @ 1000rpm)
Lubrication	Wet Sump
Gear ratio	1.73:1
Controls	Command Link® - Digital Electronic Controls
Multiple outboard synchronization	Auto sync throttle control with twin and triple applications
Trolling throttle adjustment	+/- 50 rpm increments (600 - 1000 rpm range)
Weight	25" shaft / 804 lbs
C.A.R.B.	3 – Star
Limited Warranty	3-Year Pleasure, 3-Year Government, 1-Year Commercial

From Yamaha Marine Group