How to Select Outboard Motors for Small Boats?

There's nothing better than setting out on the lake for an early morning catch in your fishing or johnboat. It's the peace and tranquility that fishing and boating enthusiasts look forward to each season. Then how to select the best outboard motors for small boats?

The Choice of the Outboard Engine

What’s the difference between four-strokes and two-strokes?

First, the technical distinction. Four-stroke outboards, like the engine in the car in your driveway, burn straight gasoline within cylinders, circulating lubricating oil through a separate system. Oil and gas don't mix, unless there's a breakdown. Two-stroke engines, in contrast, burn a blend of gas and oil. Secondly, two-strokes are lighter than four-strokes with the same power. Thirdly, four-strokes are quieter than two-strokes, but the difference is shrinking. Fourthly, two-strokes generally provide a stronger hole shot.

The Choice of Two Motors or One

Multiple motors only provide security against breakdown if they're truly independent, including fuel and power sources. Hanging multiple motors adds power only if they exceed the power available in a single. Another alternative is to run a single unit and add a satellite phone for breakdown recourse. In one word, if the price difference is not an issue, then twins are worth considering. Otherwise, a single is the simpler choice.

The Choice of Size

Choosing the right size outboard motor for a small boat is easier than you think, but the size also isn't set in stone.

Your boat should feature a capacity plate issued by the coast guard to tell you the safe and appropriate horsepower and total weight limit for your boat. In most cases, 8-20 hp motors provide plenty of power to effectively propel your boat, and you'll find you get better fuel efficiency as an added bonus. You can always move up to a larger motor if you're impatient. In contrast, smallers motor offer better fuel efficiency, less upfront cost, easier handling, and in many cases a quieter ride.

The Choice of Shaft Length

Because small boats have small transoms, you're most likely going to choose a short shaft length. While there are some small boats with larger transoms, and those will need a long shaft motor, most small boats will not require this.

To determine the shaft length required for your boat, take out a measuring tape and measure the height of the back-end of the boat from top to bottom in the middle of the stern. Your shaft length should match this.

If you're an inch off, it's not a big deal. However, 5 inches off and you've got a problem, so try to be as close as possible to matching your motor shaft to your transom height.

The Choice of Horsepower

How much horsepower do I need for my boat? While the individual concerns may be different. There are several factors to take into consideration when you’re determining how much horsepower you need.

1. Boat Horsepower-To-Weight Ratio

Let’s say, for example, your boat weighs 5,000 pounds, and it has a 300-horsepower engine. Taking 5,000 divided by 300 gives you a result of 16.6 pounds per horsepower. Doing the opposite calculation — taking 300 divided by 5,000 — gives you a result of 0.06 horsepower per pound. The lower the number, the faster your boat will go. Remember the boat horsepower-to-weight ratio once you’ve decided on horsepower and are matching outboard to boat size. While one or two outboards may give you the same horsepower result, keep in mind additional weight will accompany each additional outboard motor.

2. Fuel Efficiency

According to Boating magazine, running your gas engine between 3,000 and 3,500 rpm and your diesel engine at three-quarters throttle is the sweet spot for fuel efficiency. If you’re running a lower horsepower engine at full throttle all the time, it’s going to use more gas than a higher horsepower with less throttle. Keep this fact in mind as you consider what horsepower to choose.

3. Number Of People On The Boat

If it’s usually just you and a friend or a spouse, that weight is different than if you enjoy boating with several of your family members and friends.

4. The Insurance Considerations.

The amount of horsepower your boat has will influence your boat insurance, which is another fact to consider.