Testing the Versatility of Yamaha’s F90B

Imagine you are the leader of an engineering team tasked with creating a new engine. It must be as light and compact as possible. It must make strong bottom-end torque, reach — but not exceed — a specified peak horsepower rating, and be able to withstand extended operation under tremendous load. It must meet future emissions and sound standards and be compatible with a range of controls and electronics. And here's the kicker — you have no idea what vehicle this engine will power.

This is the very challenging everyday mission facing marine-engine designers: Please meet each of these criteria and, by the way, your new engine could end up on a bass boat or a pontoon, a heavy deck boat or a feather-weight aluminum skiff. When an engineering team at Ford develops a new engine, they know it's going to power an F150 truck that Ford will also manufacture. That's a luxury Yamaha engineers could have only wished for as they developed the new F90B outboard motor. At the end of its assembly line, the outboard is packed in a box and sent out into the world, duty and destination unknown.

Four of those new F90B outboards were sent to boatbuilders participating in a demo day that Yamaha recently organized on Geneva Lake in Wisconsin. We usually pick one boat for a test of a new motor, but in this case we were presented with an opportunity to evaluate this important new outboard on a diverse collection of boats. And so we tested the F90B four times, on four boats, to find out if Yamaha was able to create one new motor capable of many different missions.

A Key Player
Today's mega motors might get all the glory, but the 90 to 115 hp range represents the heart of the outboard market, accounting for a big sales volume that includes many first-time customers. These engines represent a critical chance to make a good first impression.

The new Yamaha F90B is based on a 1.8-liter in-line ­­four-cylinder powerhead that replaces the previous 1.6-liter F90A. The bottom of the engine is the same as the 1.8-liter F115B introduced in 2014. The key difference is the design of the cylinder head. The F115B uses a double overhead-cam head to actuate four valves per cylinder. The F90B uses a single overhead-cam head with four valves per cylinder, a design that might compromise performance a bit but is less complex (and thus less expensive), lighter in weight and more compact than the double cam. The F90B is physically smaller than the F115B in every dimension — for instance, a 90 cowl will not fit on a 115. Yamaha used some of that space on the back of the motor to locate the fuel-vapor separator in a spot where it will be easy to service.

Yamaha claims more top-end power and bottom-end torque from the new powerhead (compared to the previous 1.6-liter engines), and I would expect an improvement on the bottom just from the increase in displacement. Charging power is also improved, from 25 peak amps to 35 peak amps, with about 28 amps available at just 1,000 rpm. The F90B is not compatible with a digital control, but the new motor can be equipped with the Yamaha Multi-Function Tiller Handle (sold separately). The motor is offered with 20- and 25-inch shaft lengths, and all versions have a 2.15-to-1 gear ratio. There are nine different Yamaha aluminum and stainless-steel props up to 14 inches in diameter offered for the F90B, some featuring the Yamaha SDS (Shift Dampening System) hub, which provides the final factor in dialing in performance.

Xpress H18B
This aluminum center console skiff is designed to be rugged, easy to maintain, and lightweight for towing. The Xpress Hyper-Lift hull has a flat pad keel, a pair of lifting strakes and a reverse chine, backed by three U-channel welded stringers and a welded aluminum deck. The boat is wood-free — the transom is cored with an aluminum grid. All voids within the hull are foam-filled, which gives the H18B a really solid feel in a chop. The entire interior of the boat is protected with Xtreme Coat, a spray-on liner material that is super-durable and has just the right texture for good footing.

You buy this boat to fish shallows, back bays and stump country — environments where quick hole shot is paramount. The less weight, the better, especially on the transom. Despite the 13 percent increase in displacement, Yamaha says its new F90B weighs 13 pounds less than the F90A it replaces, 366 pounds reduced to 353 pounds for a 20-inch model. That’s nice work shedding weight, but the Yamaha is still not the lightest 90 on the market; the 1.3-liter Evinrude E-Tec 90 two-stroke weighs just 320 pounds, and the 1.5-liter Suzuki DF90 is the lightest four-stroke at 341 pounds. Both of those motors give up displacement to the Yamaha. That’s the trade-off. Testing with a light load and a Talon SS prop, the Xpress popped on plane in less than 4 seconds with no bow rise, demonstrating that displacement and torque are also part of the hole-shot formula.

How We Tested
Engine: Yamaha F90B
Prop: Yamaha Talon SS 13.125" x 18" stainless steel
Gear Ratio: 2.15:1
Fuel Load: 15 gal.
Crew Weight: 360 lb.

More Information
Xpress Boats - 501-262-5053; xpressboats.com

Alumacraft 175 Voyageur Sport
This is a fine example of a family angling rig from a quintessential Minnesota aluminum boatbuilder. Because the angling season up north can start and end in snow flurries, this boat's full-glass windshield is a popular feature. The 2XB hull features a twin plate in the bow to defend against rocks and stumps, a one-piece extruded keel, aluminum-cored transom, and concave spray rails for an exceptionally dry ride. Lockable side rod storage in the cockpit port and starboard doubles as seats for days when jigging is the preferred presentation.

Very slow trolling is a common technique in walleye waters and a reason why we appreciate the Yamaha VTS (Variable Trolling Speed) feature on the F90B. VTS can be activated through a Command Link display or a new remote switch that can be mounted anywhere in the boat. VTS permits adjustment of the engine speed from 550 (200 rpm below idle speed) to 1,000 rpm in 50 rpm increments to dial in just the right trolling speed.

The F90B provides plenty of poke, planing effortlessly and cracking a 40 mph top speed, and the Voyageur tracks like a dream through turns.

How We Tested
Engine: Yamaha F90B
Prop: Yamaha 13" x 19" aluminum
Gear Ratio: 2.15:1
Fuel Load: 17 gal.
Crew Weight: 360 lb.

More Information
Alumacraft Boat Company - 507-931-1050; alumacraft.com

Veranda VR20L
This is a great example of pontoon value. The brand-new VR20L has an attractive price but looks deluxe, with its fancy curved fence and plump upholstery, roto-molded seat bases, Simrad glass helm display, standard 8-foot Bimini, and aft sun deck. A key feature is an all-aluminum deck formed of interlocking 2-by-6-inch "planks" that are welded every 6 inches to a stout M bracket. This deck will, of course, never rot, and it's lighter than wood and very flex-resistant.

We tested the VR20L with optional twin 27-inch-diameter tubes, a step up from the standard 25-inch tubes that provide a little more buoyancy and are a good choice if you head out frequently with the entire extended family. Triple tubes are also offered and increase the rating to 150 hp. This setup is more about relaxed cruising, and the Yamaha F90B keeps it laid back with extremely quiet operation. At idle we measured just 54 dBA on our Radio Shack sound meter and really could not hear the outboard — just water and birds chirping. The sound level at 4,500 rpm is just 78 dBA. Get on an older pontoon with a conventional two-stroke outboard and you’ll wonder how we ever tolerated the racket.

How We Tested
Engine: Yamaha F90B
Prop: Yamaha Talon Pontoon 14" x 11" stainless steel
Gear Ratio: 2.15:1
Fuel Load: 25 gal.
Crew Weight: 360 lb.

More Information
Veranda Marine - 501-262-3876; verandamarine.com

Rinker 17QX
This new runabout is compact in size but very well-finished. The 17QX never makes you feel like you're in a boat that's been built to a price point. It's a good choice for the family that needs a garage-size boat that's also easy to tow, a second boat, or a boat for the kids. A full-glass windshield, stainless-steel grab rails, flip-bolster bucket seats, tilt wheel, and Kicker audio with Bluetooth are standard. Our boat had an optional ($135) red gel finish on the consoles for added sporty flair.

The power of the Yamaha F90B really came through when we ran the 17QX. The 40 mph top speed is perfect for this size boat, and the Yamaha popped the deep-V hull right on plane. The Rinker was fun to drive because it’s very trim-responsive; you can air out this hull on smooth water. It also delivers a comfortable ride, slicing through boat wakes that would rattle passengers in some other 17-foot bowriders. You can order the 17QX with a 115 hp outboard, but we say save your money. The F90B hits the sweet spot of performance and economy for this sporty little boat.

How We Tested
Engine: Yamaha F90B
Prop: Yamaha 13.25" x 17" aluminum
Gear Ratio: 2.15:1
Fuel Load: 17 gal.
Crew Weight: 360 LB.

More Information
Rinker Boats - 574-457-5731; rinkerboats.com