Small aluminum fishing boats and jon boats aren't designed for skiing or racing, so it's not necessary to outfit them with a high horsepower motor. However, they weigh more than a dinghy and require a little more thrust to move them through wind-driven waves.
Equipping your low-key incognito boat with a 75 horsepower motor is overkill, and may even be dangerous. You want something simple and quiet that can produce just enough power to move you to where you need to be efficiently and comfortably.
Small outboards in the 8-20 horsepower range are perfect options for small boats. They'll give you enough power to move across a large lake, while also offering the capability to purr peacefully into a weed-choked cove without disturbing the serenity.
Choose the Right 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 inform you on the safe and appropriate horsepower limit and total weight limit for your boat. If it doesn't, it's likely it got removed at some point or your boat is an antique that was manufactured prior to August 1st, 1973 when the USCG began requiring them.
The capacity plate is typically located on or near the stern of the boat, and the horsepower limit is important to adhere to for safety reasons. If you equip your boat with too much horsepower, you'll end up tipping the hull to the sky and sinking motor-first.
But you also don't have to equip your boat with as much horsepower as it can handle. If you're using your boat to maneuver down shallow streams, into weed-filled coves, or simply to maneuver to a peaceful spot where you plan to anchor, a high horsepower motor just isn't necessary.
In most cases, 8-20 hp motors will provide plenty of power to effectively propel your boat, and you'll find you get better fuel efficiency as an added bonus. If your boat's capacity plate lists a 40 hp maximum, a 20 hp motor should do you fine. You'll get good handling and plenty of thrust to move through choppy water. Likewise, if your boat's capacity plate lists a 20 hp maximum, it's a safe bet that you'll get by just fine with a 8 or 9 hp motor.
You can always move up to a larger motor if you're impatient, but a smaller motor will offer better fuel efficiency, less upfront cost, easier handling, and in many cases a quieter ride.
Choose the Right 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.
In fact, if you install a motor with a long shaft on a boat with a small transom, you will instantly regret it. Opening the throttle on a setup like this can cause dangerous problems. The position of the prop is important and keeps the boat stabilized when in motion.
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 the top to the 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.
Choose the Right Features
A small boat motor may not boast a lot of bells and whistles, but there are some simple features that you may find are nice to have.
Electric start is a great feature to have on any boat, but especially on small boats. When you're drifting in strong winds, a light-weight boat drifts fast. It may be cold, it may be a little rainy, and pull-starting a recoil outboard while you're rapidly drifting toward rocks is not a very fun thing to do. Electric start makes it easy to start up and move away from hazards before you're on top of them.
Power tilt is another great feature to have when you're powering a small boat through shallow waters. Especially if you've equipped your boat with a 15 or 20 hp motor that can give your shoulder a workout. Manually tilting your engine out of the water every time you cross over rock beds and sand bars will have you wanting to cut your day short. Power tilt allows you to trim up your engine with the push of a button, saving your arm and shoulder for what matters - fishing, hunting, or simply relaxing in the great outdoors.
Power thrust helps get your boat moving easier. It'll give you 60-percent more thrust in reverse and 15-percent more thrust in forward. It helps to get your boat up to speed quicker, and improves maneuverability while also helping to combat a stronger current or heavier wind.
Whatever you use your small boat for, the right small outboard engine will make for a smoother, quieter, more efficient ride. Choose the right size and features, and you'll be happy for years to come.