Model Outboard Motors for Model Boats: Electric and Glow Options
Model outboard motors are self-contained drive units that clamp or bolt to the transom of a model boat, combining the motor, drive shaft, gearbox or direct drive and propeller in one unit, often with water cooling. Small electric outboards suit scale fishing boats, tenders and toys; larger brushless and glow outboards drive racing hydroplanes and tunnel hulls, where the whole unit turns to steer. They make installation simpler because there’s no stuffing tube or strut to fit through the hull.
By Kyle HilsonUpdated: October 20264 min read
Types
| Type | Use | Notes |
|---|---|---|
| Small brushed electric | Scale and toy boats | Cheap, simple, slow |
| Brushless electric | Racing outboard boats | Fast, water-cooled |
| Glow outboards | Nitro racing | Classic racing class |
| Scale detail outboards | Display/scale | Cosmetic covers over a small drive |
Why choose an outboard
An outboard puts everything outside the hull, so installation is quick and the hull stays sealed. Steering by turning the whole drive gives sharp handling, and outboards can be tilted to adjust trim. For scale fishing boats and runabouts, an outboard looks right. For racing, outboard hydroplanes and tunnels are their own popular classes. Outboard boats are covered in RC outboard boats.
Mounting
- Reinforce the transom with plywood; outboards load it heavily.
- Set height so the prop runs at the right depth (racers fine tune this).
- Set the tilt (trim) angle to suit the hull.
- Link the steering servo to the motor’s tiller arm.
- Seal any holes for wires or cooling lines.
Cooling
Brushless and glow outboards usually have water pickups in the lower unit that pump water through a jacket around the motor. Check the pickup isn’t blocked and that water exits during running. Small brushed outboards may rely on air cooling and should not be run hard for long.
Choosing one
- Match size and power to the hull’s length and weight.
- Check voltage and the ESC it needs.
- Look for spare props and lower-unit parts.
- Choose direct drive or geared to suit the prop.
- For scale boats, look at appearance and realistic speed.
Inboard electric options are compared in model boat electric motors.
Care
After running, flush the cooling system with fresh water, dry the motor, oil the shaft and bearings where specified, and check the prop. Lower units with gears need periodic grease.
Making your own
Hobbyists build simple outboards with a small motor, a long shaft in a brass tube and a prop. For a beginner, a ready-made unit is easier and more reliable; DIY boat projects are in how to make an RC boat.
Props for outboards
Outboard performance depends heavily on the propeller. Small electric outboards come with a plastic prop matched to the motor, and changing to a larger or steeper prop can overload it and cause overheating. Racing outboards use metal props, often two- or three-bladed, chosen for the hull, motor and water conditions. A larger diameter or pitch gives more top speed but draws more current; a smaller prop gives faster acceleration and cooler running. Change one thing at a time, measure motor and battery temperatures after a short run, and keep spare props because outboard props sit low and hit debris.
Safety
Outboard props spin fully exposed at the back of the boat. Keep fingers clear when the battery is connected, arm the ESC only when the boat is held securely or in the water, and disconnect power before touching the drive.
FAQ
Can I put an outboard on any model boat?
On most with a suitable, reinforced transom.
How does an outboard steer?
The whole unit turns, linked to a servo.
Do outboards need cooling?
Powerful ones use water cooling.
Are glow outboards still made?
They remain in some racing classes; check current makers.
More on this topic: the complete RC Boats guide covers the basics behind this article.
About 20 years in RC. Mostly boats in the NAVIGA Mini Eco Expert class, with many self-made parts; also a King Motor Baja 5B, a home-built electric plane, home-built nitro planes he has flown, and an RC helicopter. More about SwellRC
