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Marine Engine Digest |
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Boating
journalist Tim Banse's
technology reviews have appeared in Popular Mechanics, Motor Boating, Yachting and
other magazines around the world.
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Home - more engine profiles - diy engine repairs - special reports Yamaha 350 HP V8 Monster Motor | ||||||||||||||||||||||||||||||||||||||||||||||
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Introducing the world's first 350 horsepower outboard motor, a 5.3L four-stroke V-8. Yamaha Marine has introduced the most potent, production outboard motor ever, the F350, a 5.3L, 350 horsepower V-8. Why so much horsepower? Outboards are growing more muscular because a couple of years ago boat builders asked engine companies to up-size motors, to make them powerful enough to lend mega zoom to 38 foot center console boats and beyond. The reason why is as simple as the sea is salt. Maximum motors work magic with big boat multiple installations. Twin or triple engines cost less to purchase and maintain and burn less fuel than triple or quad installation. With one fewer gear case dragging in the water top speed and acceleration skyrocket. So while bigger is undeniably better, the real epiphany comes with the realization that fewer motors work smarter not harder. For these reasons Yamaha Marine’s spanking new F350s would find a happy home on any big boat transom. Look for near term introduction of F350 class boats from Edgewater, Grady White, Pursuit and other boat builder partners that collaborated with Yamaha.
Beyond raw, bloody, horsepower the Yamaha F350 325 cid four-stroke boasts a startling number of tantalizing new technologies, things like ionic combustion sensors that constantly monitor fuel burn and adjust spark timing accordingly; Dimpled outer cylinder sleeves reduce oil consumption; New-generation head gaskets lock in horsepower; And updated corrosion protection fights the ravages of saltwater inside cooling passages and on external components parts. Curb weight is an acceptable 804 pounds.
Even though Yamaha is renowned for the V-8 car engines it built for Ford, the new Japanese outboard is pure marine motor. Several years in the making, it was designed from the proverbial blank page. Its 325 CID aluminum block is a 60-degree V. Cylinder heads are populated with 32 valves (four per cylinder) opened and closed by double overhead camshafts. Cognoscenti already know variable cam timing optimizes torque at low and mid-range, exactly the rpm where boat motors log the majority of engine hours. Sequential, multi-point fuel injection pours on the fuel in precise spurts. Technophiles will rub their hands together in glee when they learn about the eight, long intake tracks flowing a massive volume of air into the combustion chamber and how special chambers relieve exhaust pressure. Translation: Not a drop of horsepower is squandered. Naturally, throttle and shift controls are electronic, with automatic, multi-engine synchronization. Twin and triple installations are the rule for now, quad commandos have to wait a spell.
One of the biggest engineering challenges in building an outboard motor packing a 350 hp wallop is designing a gear case robust enough to stand up to the massive torque. Confidential sources whisper from the shadows that competing brands of Uber outboards are waiting in the wings as engineers learn special methods for keeping pinion gears from stripping their teeth. So it should come as no surprise to learn the Yamaha F350 features hardened gears and ultra heavy-duty bearings for maximum durability. Even motor mounts are forged and the mount bracket oversize. © Copyright 2007 by Tim Banse
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