Self-manufactured outboard motors are not just a way to save a significant amount of money, but also the opportunity to get a unique unit that is perfect for your swimming equipment. Many anglers and outdoor enthusiasts are thinking about creating a homemade engine when factory models are too expensive or too powerful for their needs. Electric motor, assembled by hand, often wins over industrial analogues in maintainability and simplicity of design.
In this article, we will discuss in detail the main types of homemade engines that can be manufactured in a garage or even a home workshop. transmission shaft It's a device that requires precision, but it's worth it.
Before starting to purchase materials, you need to clearly define the type of boat and operating conditions. PVC It will require a completely different approach than a heavy metal boat, and the correct calculation of power and thrust will avoid overload and ensure comfortable movement on the water.
power selection plant: electric motor or internal combustion engine?
The first and most important step is to choose the source of energy, and homemade motors fall into two big groups: electric and gasoline. Electric motors They're becoming increasingly popular because they're green, quiet and easy to maintain, and they're perfect for fishing, where noise can scare off prey.
Gasoline units converted from chainsaw They're more autonomous and powerful, but they're more complex, they require adjustments to the carburetor, the ignition system, the exhaust system, and they also require more robust attachment to the transom.
⚠️ Attention: When using homemade gasoline engines, it is extremely important to ensure reliable exhaust exhaust exhaust and protection against spark formation to eliminate the risk of fuel vapor fire.
For beginners with no experience with ICE, we recommend starting with an electrical circuit, which is safer, cheaper to implement, and forgives many build errors. Battery battery Weighing 10-15 kg easily carried and charged from the usual network.
The table below compares the key specifications of both types of engines for homemade projects:
| Parameter | Electric motor | Petrol (PIC) |
|---|---|---|
| Noise | Minimum | High. |
| Difficulty of assembly | Low. | High. |
| Structure weight | Depends on the AKB. | Lighter (excluding fuel) |
| Cost of launch | Low. | High. |
The choice depends on your priorities: silence and simplicity or power and range. Weigh all the pros and cons before you start work.
Required tools and materials
It takes a standard set of home craftsmen to make a good engine, and you don't have to try to build a machine on your knee without the right tool, because the reliability of the design has a direct impact on your safety on the water. direct-currentYou can get it out of an old electric truck or buy a new one.
You will need the following components to build the electric version:
- 🔧 A drill or screwdriver with a set was drilled on metal and wood.
- ⚡ A powerful battery (usually 12V or 24V) and a speed controller.
- 🛠️ Materials for lower unit (pipe) and propeller (brass or aluminum).
- 🔩 Fixing elements, clamps and sealant for insulation.
Pay special attention to the selection of materials for lower unitIt's a tube that spins a shaft inside, and it has to be resistant to corrosion and mechanical damage, and it often uses stainless steel or strong plastic.
If you plan to make a gasoline option, the list will be replenished with a fuel tank, a jamming system and a more complex clutch mechanism. Quality of materials Determine the life of your product.
Manufacture of propeller and lower unit
The propeller is the heart of any motor, whether factory or homemade, that converts the rotational motion of the shaft into the forward motion of the boat, and the easiest thing for a homemade motor is to make a 2 to 3 mm thick sheet aluminum screw. The optimal diameter of the screw for the engine with a capacity of up to 1 hp is 150-200 mm.
The manufacturing process is as follows:
- ✂️ Cut out a circle of the desired diameter from the metal.
- 🌀 Mark the blades (usually 3 or 4) and make slots to the center.
- 🔨 Curve the blades at the right angle (screw step) to capture water.
- 🔩 Fix the screw to the engine shaft using a tsang clamp or threaded connection.
lower unit must be strictly perpendicular to the rotor's plane, any distortions will cause vibrations and loss of efficiency. To seal the shaft coming out of the pipe, use glands or homemade seals of rubber.
The secret to improving the efficiency of the screw
To increase the efficiency of the homemade screw, you can polish its blades to a mirror shine, which will reduce friction against the water, and round the front edges of the blades for better entry into the water flow.
It is important to check the rotor's balance before installation. The imbalance will cause the shaft to beat, which will quickly destroy the engine bearings. Balancing carry out by putting the screw on a thin axis and checking the horizontality at rest.
Electrical traction assembly: step-by-step instructions
The assembly of an electric motor begins with the mounting of the engine on the stan, often using a profile pipe or a wooden timber treated with olifu, the engine must be rigidly fixed to prevent displacement under load.
Then there's the electrical connection phase, the speed controller (ESC) connects between the battery and the engine, and it allows you to adjust the speed and speed of the boat, and all the contacts must be sealed and thermally insulated.
☑️ Checklist of assembly of electric motor
You can use the usual speed control potentiometer With a tumbler or a specialized gas pedal, handling convenience is a key factor in comfortable operation.
⚠️ Warning: Never test an electric motor without fixing the body. At a sharp start, the screw can create a jet moment that overturns the loose device.
After assembly of the entire electrical circuit, you need to check the system operation in the air (shortly) and make sure that the contacts do not spark and overheat. Tightness The connection is the key to the long life of your motor.
Chainsaw adaptation for the boat
Use of the engine chainsaw The classic liquid fuel option is to transfer the torque from the saw shaft to the propeller shaft, and you can't connect directly because of the different speeds and directions of rotation, so you need a gearbox.
The gearbox is often used with an angular gearbox from an old Bulgarian or a differential from a car (for high-powered engines), and the chainsaw shaft connects to the gearbox via a centrifugal clutch or belt gear, which allows the engine to start without loading.
The design is attached to the trunk of the boat with the help of rods or clamps, and it is important to provide the possibility of tilting the lower unit to overcome shallow water, as is done in factory models. Cooling system In such engines, usually air, so it is important not to block the air flow with casings.
When using a chainsaw engine, be sure to install a spark on the exhaust pipe, as the gasoline vapor in the boat's hold can flash from an accidental spark.
The fuel tank is located above the carburetor for gravity or use a fuel pump. The volume of the tank is calculated based on the engine consumption (usually 0.5-1 liters per hour for engines up to 2 hp).
Testing and first launch
The first start of a homemade motor is a crucial moment: start the tests in a tank of water (barrel, bath) or in shallow water, securely fixing the engine, which will detect leaks, vibrations and cooling problems without risk to the boat.
Check the different revs. The engine must not stop when loaded, and the screw must confidently push water. If the motor is electric, watch the temperature of the engine body and controller.
During the break-in (especially for gasoline versions), check the tightening of all bolt joints. Vibration has the property of unwinding even well-tightened fasteners. Regular examination After the first hours of work is mandatory.
The success of the first launch depends on the quality of pre-assembly and testing all components for dry, without immersion in water.
If it's a success, you can try it out. Don't go at top speed right away, let the knots warm up and get lost in each other.
Frequently Asked Questions (FAQ)
What is the minimum power required to move a PVC boat from its place?
For a light single PVC boat, an electric motor with a capacity of 100-150 watts (about 0.2 hp) is enough. For two people with a load, 200-300 watts will be required. Gasoline engines make sense starting from 2 hp, since smaller power will not give a tangible advantage over oars.
Can I use a car battery for a outboard motor?
You can use a car starter battery, but you don't recommend it, because they're not designed to give off current in small portions for long periods of time, and they're afraid of deep discharge, and you'd better use traction batteries (GELs or AGMs) that are designed for electric motors.
How to protect a homemade motor from corrosion?
All metal parts in contact with water must be made of stainless steel, brass or aluminum with anode coating. Steel elements must be carefully painted with anti-corrosion paint or use zinc treads (anodes) that are installed on lower unit.
Do I need to register a homemade motor in GIMS?
Under current regulations, registration is required for small vessels with an engine of more than 8 kW (about 10.8 hp). If your homemade motor is weaker than this threshold and the boat does not exceed 200 kg of weight, registration is usually not required, but the rules may change, so it is worth clarifying the current information.