How To Make A Boat Motor From A Trimmer

Making a boat motor from a trimmer
How to use a lawn mower outboard motor correctly? Review of making a boat motor from a trimmer: do-it-yourself algorithm

Method number 2

To assemble a boat ICE, the manufacturer will need to prepare an angular gearbox that can be removed from an angle grinder. Also, for alteration, a propeller is needed. It can be cut from a sheet of stainless steel and the resulting blades bend at the desired angle.

how to make a boat motor from a trimmer

Despite the relatively small pitch of the resulting screw, this alteration method makes it possible to achieve the maximum possible speed from the engine. The only drawback is the need for additional engine adjustment, for which you can use pliers.

Methods for making a boat motor from a trimmer

There are three ways to make a trimmer outboard motor. They differ from each other in the parts used and the principle of self-assembly.

Method number 3

This method differs from others in the ability to make some parts for the boat engine with your own hands. This requires a 2-stroke gasoline engine with a cylinder volume of 25 cm3. The engine power from the trimmer should not be less than 0.7 kW, and its weight should not be more than 4.5 kg. The unit must be equipped with a bent leg. A trimmer engine that meets all these parameters will make it possible to move the boat at a speed of 5 to 8 km / h with minimal fuel consumption. We will describe in more detail the principles of its manufacture below.

What are homemade boat motors made of?

If desired, a motor for a light boat can be made by yourself. In most cases, ready-made tools are used as a basis.

The following are often used:

  1. The grass mower is ideal for creating a trimmer. It is designed for long-term use, so it can last for a long period.
  2. In some cases, a construction mixer is being reworked. In this case, batteries act as source of energy. This version is ideal for quiet fishing, but it is not designed for long-term use.
  3. A gasoline saw is rarely used. However, its design features determine that it is necessary to carry out a serious alteration.

Benefits of using a trimmer

The trimmer has quite a number of advantages that determine its distribution.

The main ones are the following:

  1. Relatively low cost.
  2. Ease of assembly and disassembly.
  3. Light weight.
  4. High speed achieved while driving.
  5. High power rating, often excessive.
  6. Economical.
  7. Initially, there is a throttle stick and a starter.
  8. There is a special leg that allows you to adjust the power of the device.

These and many other qualities determine the fairly widespread use of trimmers in recent years.

Principle of operation

When considering a trimmer, attention should be paid to the fact that such a mechanism provides a high speed of rotation of the blades. This ensures a high speed of movement of the boat through the water.

The features of the principle of operation include the following points:

  1. The blades are turned outward.
  2. The installed motor in the upper part transmits the rotation of the blades.
  3. To increase reliability, the shaft that connects the motor to the blades is located in a protective tube.

Making a mount for installing an engine on a ship

You can install a homemade boat motor from a lawn mower using a ready-made clamp. But if you have an old hand sander lying around in your garage, making a mount for the engine, with which it can be installed on the transom, will not be difficult:

  1. Using an angle grinder, cut out the bottom of the grinder and drill a 12 mm diameter hole in the transverse plane of the housing.
  2. Flatten one end of a hairpin with a cross-section of 12 mm and a length of 100 mm and drill a hole with a diameter of 6 mm in the resulting plane.
  3. Insert a bolt with a suitable cross-sectional diameter into the hole obtained. The trimmer ring, originally intended for attaching the belt, will be fitted on it.
  4. The DIY mount can now be connected to the boat’s transom using a stud and nut. Install the motor and secure with the appropriate nut.

Ready set of attachments

Now they sell special attachments for converting the trimmer into a boat motor. This attachment includes everything you need to attach to the lawn mower motor. A control handle and a switch button are mounted to the rod. The throttle handle is made with the ability to switch speeds and is equipped with a ratchet that secures the required position.

Making a screw

To create a screw, you need a duralumin strip 100 mm long and 30 mm wide. If you put the screw on the table, then the distance from it to the blade should be 10 mm. The angle of inclination of the propeller blades must be adjusted with pliers. Before this, the duralumin is annealed. Propellers with 2 or 3 blades can be made in various sizes. The propeller dimensions should be selected individually.

Trimmer motor: features

The idea to use as a boat engine from something else has occurred to more than one home craftsman. As a result, they learned how to make a motor for a boat with their own hands from a lawn mower, a screwdriver, and, of course, lawn mowers. Of course. Because the cost of a lawn mower is an order of magnitude lower compared to a motor, and the drive power is quite acceptable.

It is easiest to make a motor from a trimmer, since the device has all the necessary mechanisms:

  • Economical engine. Especially when it comes to a four-stroke. In most cases, of course, a two-stroke is used, since its cost is lower;
  • Built-in fuel tank, almost always transparent, so that the fuel level is easily controlled;
  • Ready-made controls. Starter, gas;
  • A rod with a rigid shaft that transmits torque.

How to make a homemade boat motor from a trimmer

Converting an ordinary boat, even a rubber one, into a motorboat is as easy as shelling pears: you need to install a gasoline engine on it. Electric is not valued by our fishermen: a heavy, low power reserve and there is no way to recharge it during a long fishing trip. However, the cost of even the simplest option for a boat is hefty. 20-30 thousand rubles.

Making a homemade boat motor

Required tools and materials

  • Trimmer. For a small rubber boat, a device with a capacity of 0.7–0.8 kW is sufficient. According to users, even with such a drive, the boat moves at a speed of 5-7 km / h. For steel, more powerful drives are used. In this case, you must also take into account the weight of the machine.
  • Duralumin for the screw, 2 mm thick.
  • A clamp or other device to secure the engine to the boat.
  • Welding machine. You can do without it only if all the necessary parts are purchased.

Trimmer Boat Motor

The idea of ​​a lightweight outboard motor for a small boat, including a rubber one, is of interest to many fishermen and not only. A motor that could become an alternative to an electric motor with heavy and not cheap batteries and a short power reserve plus not the ability to recharge in nature is a dream for many. If we add the relatively low price and versatility, then there is the possibility of using it for other useful purposes. Then the trimmer motor (lawn mowers or lawn mowers. Call it what you want). Not a very bad option. And if you already have a trimmer, it wouldn’t be bad to use it as an engine for a boat.
Why a trimmer? Light, modern, “low drinking” motor with a built-in tank, with ready-made controls: throttle handle, starter. There is even a long “leg”, what else is needed?

And it is necessary to adapt this unit to the boat so that it performs the functions of a boat motor. And there are various options here.

The first, the simplest, although not the cheapest. Buying the necessary parts.

– Clamp for attaching a homemade boat motor from a trimmer to the boat transom

Although it is not necessary to buy ready-made, it is quite possible to make it yourself. A bit of imagination and straight arms.

The attachment to the lawn mower is explained in the instructions and takes no more than 30 minutes, with all the preparatory work.

All. You can test ready outboard motor from trimmer and install on the boat.

You have a trim tab, but you don’t have a boat. We make a simple boat with our own hands. The main thing would be hands 🙂

Second option modification of the mower for a boat motor

We do it as much as possible with our own hands. It is proposed to consider using a specific example of the craftsman Vigovsky I.

Weedwacker petrol trimmer. (It is clear that you can use any other with similar characteristics)
Engine: two-stroke, 25 cm3Power: approx. 700 W.Weight: 4.5 kg.With a bent leg.

The lawn mowers rework consisted of the following:

Alteration of the bent shaft.First of all, I removed the standard nut (2) from the line reel. It is a 20 mm long tube. With internal thread. If you cut it, you get two 🙂Important. Nuts must be taken care of, as cunning manufacturers have invented their own threads. Not metric or inch.Then he took off and threw away the plastic cover with the gas button.

1. Cone rubber (auto part).2. Nut (standard).3. Screw.4. Nut (standard).5. Groove for bushing pressing.6. Bronze bushing (standard).7. Dural tube of suitable diameter.8. Stern shaft.9. Flexible shaft10. Plastic protector of the flexible shaft.

There are no roller bearings at the end of the bent pipe, but there is an ordinary bronze bushing (sleeve bearing) (6). This sleeve must be carefully cut. To do this, do not forget to remove the flexible metal shaft (9) from the pipe, unscrew the nut (4), and remove the stern tube (8)After removing the bronze bushing (6), we knock out the plastic protector of the flexible shaft (10) from the metal bent pipe, and discard the pipe, since it is steel and all attempts to straighten it did not lead to anything.Instead of a standard pipe, I picked up a duralumin one with about the same inner diameter. I pressed a bronze bushing (6) into it, having previously grooved it a little (a pipe of a slightly smaller inner diameter) and pressed it along the groove (5) with a hammer, but carefully and gently so as not to damage the bronze bushing.The plastic protector (10) was slightly cut in diameter and tightly inserted into the tube. If the outer diameter of the tube turns out to be large and does not fit into the hole for attaching to the motor head, then it must be cut to size.If you wish, you can make the shaft longer than the standard flexible one. It is necessary to take a pipe of the length you need, and install a steel bar of the required length in place of the flexible shaft. So the shaft is ready.

Making a screw.It is not necessary to adapt the screw to the mower from “Salute” or god forbid from “Vortex” they won’t fit. It can be done much easier.We take a strip of 2 mm. Duralumin size 100×30 mm. And process according to the drawing. We sharpen the edges.

The pitch of the screw is about 10 mm, that is, if you put the plate on the table, then you need to bend the blade to a height of 10 mm, then bend the second blade.The screw is easy to adjust. If the revolutions are not high, you can cut the blades or adjust the pitch of the propeller, using pasats with preliminary annealing of the duralumin.Fasten the screw with the nut (2) and hold it fairly tightly. No key required. If the propeller hits something, the motor simply stops.

Attention: it is possible and necessary to make a ring nozzle, since you can accidentally screw the boat’s cylinders with a screw.

Gaza Strip.The native plastic pipe cover with the gas button was mercilessly thrown away. Instead, I bought a bicycle derailleur and installed it on the body.And one more thing: in the future I plan to change the direction of the exhaust gases towards the propeller.

Fastening the shaft to the motor.Made from 20 mm. Laminated plywood, two plates that are attached to the motor head and clamp the shaft with four screws. The shaft can be detached during transport

Operation results:The motor was operated for one season, that is, all summer on Saturdays and Sundays and one long trip for 25 days. During this time, 15 liters were burned. 92 gasoline.
The engine should be run-in with a mixture of gasoline and oil 1:40 (as in the passport). It is enough to burn one tank (0.5 liters) for running-in. Next, you can dilute gasoline with oil in a ratio of 1: 100. This has been tested and does not affect the condition of the motor.On one tank (0.5l.), In Stihl, you can drive about 10 km.

Speed ​​under the motor for a boat from a mower (measured by GPS):Catamaran type “Spaciousness” weighing 120 kg., in Stihl, with one person on board. 7.9 km / h.Catamaran type “Spaciousness” weighing 120 kg. With one person and junk on board the catamaran “Albatross” with two people and junk, in tow. 5.6 km / h

And another version of the propeller

This option using the bevel gear from the angle grinder

Oil seal assembly. Stuffing box. From the distributor VAZ 2109. Oil seal. External, pressed with a washer, fastened with three screws along the radii.

Reducer from an angle grinder made in China. Both bearings were replaced with new ones, the rear support was left with the old one (it is needle-shaped there, native). The reducer is assembled for sealant.

With the gearbox, the motor began to reach maximum speed even with a significant pitch of the screw (it still needs to be adjusted in the field, since this is done with pliers). The screw is cut from a stainless steel plate. This increased the thrust and hence the speed of the boat.

Choose any method and use the lawn mower not only for its intended purpose, but also as an excellent alternative to a boat engine.

Motor gearboxes in stock on our website

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