Outboards & Trolling Motors

Outboard Motors, Generators, Powerheads, Gear Cases & Outdrives How-Tos

Outboards, Sterndrives, and Inboards: Comparison

Outboard motors, also known as OB's, are the most common motor in the marine industry.The outboard motor is mounted to transomand is visible from the steering wheel. The horsepower range is between 1.5hp to 350 hp. Outboard motorscan be 2 stroke or 4 stroke motors. The 2 stroke motor will have the gas and oil mixed in the gas tank. The 4-stroke outboard motor will mix the oil inside the motor. Outboard motors can have 1 to 4, and 6 cylinders.

The motor can be started with a pull start cord similar to a lawn mower for the smaller horsepower. They are often used for fishing and are steered sitting at the back by the transom using a tiller handle attached to the motor. Larger outdoor motors have a key start and are steered with a steering wheel at the front - usually used for vessels with more speed used for water sports or for cruising.

Outboard motors with a Key Start or tiller handle

Outboards, Sterndrives, and Inboards: Comparison Outboards, Sterndrives, and Inboards: Comparison

Outboards, Sterndrives, and Inboards: ComparisonOutboards, Sterndrives, and Inboards: Comparison


Sterndrive motors are also known as I/O's, which stands for Inboard/Outdrive. The inboard motor is under the deck at the back of the vessel and the outdrive comes out of the transom around the water line. The inboard and outdrive are connected with a universal joint that allows the outdrive to move, which changes the direction of the vessel. These motors are always key start and steered at the steering wheel. I/O's are all 4 stroke motors, with 4, inline 6, V6 or V8 cylinders. They can be purchased as single propeller or as dual propellers outdrives. I/O's are usually higher horsepower motors. Since the sterndrive engine comes out of the lower transom, it doesn't get in the way when fishing or trying to pull up to the dock. The price is usually attractive for a sterndrive and there are boat models that require only sterndrive motors.

Outboards, Sterndrives, and Inboards: Comparison


Inboard motors, also known as IB's, are marinized versions of Chevrolet and Ford automotive motors. They are placed either in the center of the vessel or back at the transom under the deck. The propeller comes out of the bottom of the hulland is steered with a rudder placed behind the propeller at the back of the boat. They are often sold in either gasoline or diesel fuel options.

Inboards are great motors for extreme water sports. With the propeller underneath the boat, there is less opportunity for someone to get too close to the propeller while in the water or doing water sports.

Outboards, Sterndrives, and Inboards: ComparisonOutboards, Sterndrives, and Inboards: Comparison

4 Stroke Outboard Motors

4-Stroke outboard motors: History, Description, Pro's and Con's

By Bill Gius, iboats.com

If it appears you're seeing more outboard powered boat on the dealership floor these days, you're right. A veritable tsunami wave of change has moved boat builders away from the traditional stern drive power to an outboard motor application.

In some cases, using the same hull design.

The industry-wide change can be partially attributed to the introduction and development of the four-stroke (4-stroke) outboard. 4-stroke outboard motors now range in power from 2hp through 350hp (excluding some higher horsepower high performance outboard motors).

Honda brought their 4-strokes to the US in the late 60's, (first Honda 3hp shown) Yamaha in the mid 80s (current 350hp Yamaha cut away shown) and Mercury (current 150hp Mercury shown) in the mid 90s.

4-Stroke outboard motors have grown in popularity because many of them are more economical, fuel efficient, quieter, ecologically friendly and easier to maintain than stern drives.

But you just don't walk away from a popular and successful design or hull if you're a boat builder.

Here is a stern drive boat with... outboard power.

The Starcraft SCX 210 OB (outboard) could be called a "hybrid" boat. The hull and most of everything above the waterline is still basically a stern drive designed boat; with a 200hp outboard hung on the back. Well, "hung" is a bit of an over simplification. You don't really just "hang" an outboard on the back of a boat that used to have its engine inside the transom. The folks at Starcraft worked with Armstrong and Yamaha to power up this great family bowrider.

According to Peter Barrett, VP Marketing for Starcraft: "We spent many R & D hours with Armstrong getting the boat to balance correctly. We have had a long relationship with Armstrong and they were eager to help us with this project. We're very pleased with the performance considering the overall size of the hull and the depth of the cockpit area."

"Our goal, first and foremost was to duplicate the rear seating comfort and utility that we had in the SCX I/O series. We did so by keeping the same design as the I/O, moving away from a traditional space killing splash well and converting the engine area into a generous storage area. Key features such as the flip up sundeck, large rear facing stern seating combined with a big usable stern swim and ski platform would all be lost without the use of a bracket on this outboard model. This stern swim platform really makes this boat a fresh water or salt water tow sports animal!".

The SCX210 OB we drove was equipped with Yamaha's newest 200hp 4-stroke outboard. It features an inline, 4-cylinder, 2.8L, 16 valve, DOHC motor that delivers a very thin profile for single or dual engine application. According to Yamaha: "this new four-cylinder, four-stroke F200 is the lightest 200-hp four stroke on the market and can easily replace lower horsepower or larger V6 outboard motors and thereby increase the performance of mid-sized boats." As you can see in some of these photos, the outboard installation not only gives the boat a lot of useful deck room but the location of the installation perfectly balances the boat in the water. It's not bow high or sitting squat in the water.

The SCX210 OB has a custom wakeboard tower and you know, so do a lot of boats these days. Even pontoon boats have wakeboard towers; that doesn't necessarily make them good wakeboard boats. The SCX is a decent wakeboard boat. It's not an inboard tournament boat; it's a very nice bowrider that puts up a good wake. We ran it at 18mph, 28mph and 40 mph; wakeboard, tubing, slalom and barefoot speeds. WOT speed was 42.3mph.

You have to pay attention to trim and speed but you can create a nice wakeboard wake that will give you good air. At slalom speeds the wake flattens down enough for recreational skiing but at barefoot speeds the turbulence off the prop is very rough. The 2,500 pound boat puts a nice hole in the water so it also gives a pretty health wake for barefooting. Depending on how crazy you want to get for tubing, it will deliver a lot of fun behind the boat.

The stern drive design also give the boat tremendous stability. We attacked some wakes from a couple large cruisers and it cut the wakes beautifully without delivering a violent shudder to the passengers.

This boat clearly exemplifies the transition from stern drive power to outboard power. It's done well while expanding and extending the life of an exceptional hull design.

For more info on the Starcraft line of boats and to find your nearest Starcraft dealer click on: //ww2.iboats.com/Starcraft_Boats/nb/m1466-y2013/ For more information on Yamaha Outboards check out: //www.yamahaoutboards.com/ For more information on Armstrong Transom Brackets click to: //www.armstrongnautical.com/brackets.htm

Bill Gius is a three-plus decade marine industry veteran with extensive, hands-on accessory, boat and engine experience. Bill has been working with iboats.com for six years to help manufacturers and dealers use iboats' online marketing, advertising and lead generation services. Bill can be reached at 800-869-1686 x199 or bill@iboats.com.

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