Grass trimmer conversion kit for boat motor

Making a boat motor from a grass trimmer

These days, an ordinary household grass trimmer is not just a tool for garden and yard maintenance. This is also the basis for self-assembly of various units useful in the economy, the list of which includes a boat motor on the basis of a trimmer for grass. One of the main advantages of boat motors from brushcuts is the simplicity of their assembly and ease of maintenance. Thanks to this, even a beginner can cope with the construction and operation of the boat engine from a grass trimmer.

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

The method

This method stands out for its simplicity and economy.

For the work will need to prepare:

  • A clamp, which is needed to attach the device to the transom of the boat;
  • Propeller. you can buy a ready-made propeller in a store. The unit comes standard with a drive unit made of stainless steel and adapters to be connected to the flexible shaft of the utility trimmer. Some models of propellers are supplied for sale together with screws, so the buyer will need to clarify the set of parts included in the set in advance.

As a rule, in the kit to the propeller there is already a ready-made drawing. This makes it possible to save money on finding the necessary schemes for work. A boat motor takes about 1 to 1.5 hours to assemble.

Method

To assemble the boat engine, the maker will need to prepare an angular gearbox, which can be removed from an angle grinder. Also for the remake you need a propeller. you can cut it out of a sheet of stainless steel and bend the resulting blades at the desired angle.

Despite the relatively small pitch of the resulting propeller, this method of modification makes it possible to achieve the maximum possible revolutions from the engine. The only disadvantage is the need for additional adjustment of the engine, for which you can use pliers.

The method

This method differs from the others with the ability to make some parts for the boat engine with your own hands. You will need a 2-stroke gasoline engine with a cylinder volume of 25 cm3. Power of the engine from the grass trimmer should not be less than 0.7 kW, and its weight. no more than 4.5 kg. The machine must be equipped with a bent leg. The engine from the trimmer for grass, which meets all these parameters, will make it possible to move the boat with a speed of 5 to 8 km / h at a minimum fuel consumption. The principles of its manufacture will be explained in more detail below.

How to make a boat motor with your own hands from a grass trimmer?

To assemble a motor from a grass trimmer on a boat, the maker will need to prepare the following equipment and materials:

  • household lawn mower
  • clamp. If it is not available, you can use any other attachment for reliable fixation of the motor on the boat;
  • sheet of duralumin, the thickness of which should not be less than 2 mm;
  • welding machine;
  • a set of fasteners;
  • screwdriver and wrench set.

To assemble a homemade propeller, the manufacturer will need drawings. They must specify the exact dimensions of the blades and how to fix them on the axle.

It is necessary to remember that the lower power of used drive and boat weight is, the smaller blades should be. For example, for a boat with a maximum weight of 120 kg a propeller with blades 10×3 cm will do.

After preparing the equipment and carefully studying the drawings, you can begin assembling the homemade.

The work algorithm should look as follows:

  • First of all, the manufacturer will need to refine the bent shaft. First you need to dismantle the factory nut, placed in a reel with a pre-wound fishing line. The nut itself is shaped like a small 2 cm tube with an internal thread. If necessary, it can be split into two small, complete nuts. When removing the fasteners, you must be extremely careful not to lose them. If this happens, it is no longer possible to find another suitable fastener;
  • After removing the nut, you will need to remove the plastic pad located on the throttle button. There are no roller bearings on the end of the standard bent rod. They are replaced by an ordinary bronze sleeve, which is often called a plain bearing. It must be carefully removed. Before this you will need to unscrew the nut, as well as remove the deadwood and metal shafts from the tube;
  • Then go on to knock out the plastic protector located on the flexible shaft. In the future, the steel tube can be thrown away, as it can not be aligned by improvised means. It can be replaced by a duralumin tube with the same diameter. In it you will need to install a bronze sleeve, which will need to move along the canvas with a hammer. Next, you need to take a pre-cut to the diameter of the plastic protector, and install it on the pipe;
  • The next step is to make the propeller. For this you need to cut the duralumin blades and sharpen their edges. After that, each blade has to be bent upwards by 1 cm so that the pitch of the propeller is at least 10 cm. To fix the finished device you can use a nut;
  • Next, you need to install a bicycle gear shifter on the boat motor from the brushcutter, which will replace the regular plastic cover. After that, it will be necessary to install a muffler, which will divert the engine exhaust away from the driver of the boat;
  • To secure the boat motor from the lawn trimmer, it is necessary to use two sheets of plywood. After that it is necessary to clamp the shaft, using 4 screws for this purpose. During transportation of the boat motor from the grass trimmer, the shaft can be removed.

After the homemade nozzle is ready, you need to run it in. For this you need to prepare a fuel mixture of fresh gasoline and engine oil in the ratio 40:1. After that it is required to pour the ready mix into a regular tank of the boat engine, start it, and let it work out a full tank of fuel at idle speed. After running-in, the homemade boat motor from a grass trimmer will be fully ready to work.

What is the nozzle for converting a grass trimmer into a boat motor?

Light boat motors are often made from a grass trimmer.

The basic ones can be called the following:

  • A clamp for installing a homemade construction with a trimmer on the prepared transom of the boat is very widespread. This option is considered more affordable, but is characterized by increased efficiency in application. The special design allows to use the device as a propeller. While performing the usual function of a motor, the mechanism has a small size, easy to install and remove, which determines a very wide distribution.
  • Propeller. This version is a bit more complicated than the previous one, but there are ready-made mechanisms on the market which are characterized by a higher efficiency of use. It is not recommended to carry out the most powerful version of the design, as due to the resulting thrust, the lightweight PVC boat can simply flip over. Often includes a special drive, made by using corrosion-resistant steel, as well as some adapters that make the grass trimmer almost a universal boat motor.
  • Another common option, let’s call the conversion of a standard mower into a motor, used to create traction. In this case, it is recommended to give preference to common trimmers, which require gasoline to work. Relatively low weight of 4.5 kg is a significant advantage of this design.

Note! When choosing, you should consider the principle of operation of the design. The wrong grass trimmer will not last for a long time.

Principle of operation

When considering a grass trimmer it is worth paying attention to the fact that such a mechanism provides a high rotation speed of the blades. It provides a high speed of the boat moving on water.

The following points can be attributed to the peculiarities of the principle of operation:

  • Blades turned outward.
  • The motor installed in the upper part transmits the rotation to the blades.
  • To increase reliability, the shaft, which connects the engine with the blades, is located in a protective tube.

Note! The higher up is the grass trimmer, the higher is the developing speed. The main disadvantage of such a motor can be called a strong noise at the time of operation. This factor is very important at the time of fishing, because the noise can scare away all prey.

Advantages of using a grass trimmer

The grass trimmer has quite a few advantages, which determine its distribution.

The main ones we will call the following:

  • Relatively low cost.
  • Easy to assemble and disassemble.
  • Low weight.
  • High speed achieved when driving.
  • High power rating, often excessive.
  • Economical.
  • Initially, there is a gas knob and a starter.
  • There is a special foot, which allows you to adjust the power of the device.

These and many other qualities determine quite a wide distribution of trimmers in recent years.

Model of a chainsaw

It is possible to assemble a model from a chainsaw, if there is a ready-made dewood. Also, the model will require a good stand. It is rather difficult to make it yourself from a pipe. Screws are used most often of a small size. However, in this case much depends on the chainsaw power. Directly the clamp is fixed behind the starter. In order to protect the device from water, a cover is used.

A long rod is used to secure the stand. It should be soldered in a vertical position. Homemade boat motors from chainsaws with water pumps are rare these days. It is also important to note that the clamp must be fixed together with the metal corners. Some use screws or clamps for this.

Principle of operation

Grass trimmer has a higher speed of rotation of the blades, which makes it possible to move through the water with higher speed, which will allow you to start fishing faster than with a motor. Everyone has seen how the grass trimmer works. how it mows the lawn and regular grass, but here, its blades are twisted in the other direction and at the same time, serves as the most economical motor.

But if the grass trimmer is lower, the speed will be lower. But the most important disadvantage of trimmer compared to conventional boat motors is that they are very loud, and they should not be used at full volume, if you do not want to scare the fish.

Features of the homemade engine

When re-equipping the motor, you should consider that they were designed to perform different functions. Grass trimmer operates at high revolutions and a small torque, and the boat motor should do the opposite. Therefore, redesigning the device requires special tools and even a drawing.

The engine of the trimmer for grass is more convenient and easier to construct, since it has a number of necessary component mechanisms:

  • very economical engine;
  • mounted unpainted fuel tank, allowing you to easily control the amount of fuel;
  • The presence in the device starter and gas;
  • Boom, equipped with a rigid shaft.

It remains only to buy the missing parts or make them yourself and you can proceed to the manufacture of the motor for the boat.

Grass trimmer functions at high rpm and low torque, while a boat motor should do the opposite

What you can do

There are several possible options for refining the grass trimmer under the motor for the boat.

Take as a rule, on every fishing trip, the first thing to start.

A very simple way, but requires additional financial costs.

It will be necessary to buy such parts:

  • Clamp for attaching the device to the boat transom.
  • Propeller. You can buy a ready-made set through the Internet, as in stores such products may not be. Included is a special drive, made of stainless steel, as well as universal adapters for flexible shaft trimmer for the grass, which allows not to bother with the fact that they will fit your model of lawnmower or not.

Tip! Sometimes in the set may be a clamp, so before you buy it to clarify what is included.

You can find a drawing of the trimmer attachment in the instruction manual. Installation takes about half an hour.

For this method, you need an angle reducer from an angle grinder, a screw that you can cut from a sheet of stainless steel, as well as gaskets and bearings for the fixture. This way to get the maximum rpm despite the small pitch of the propeller. In the field, the device requires additional adjustment, which is done with the help of pliers.

This procedure can be carried out by hand as much as possible. Let’s consider it in more detail on the example of a lawnmower with a two-stroke motor of 25 cm3. The 700 watt, 4.5 kg device is equipped with a bent leg. Grass trimmer with such power allows the boat to move at a speed of about 5-7 km / h.

For conversion you’ll need an angle gearbox from an angle grinder, a screw, which can be cut from a sheet of stainless steel, as well as seals and bearings for fixing

What will be needed

To make it, you will need materials, as well as tools:

  • Grass trimmer.
  • Duralumin with a thickness of 2 mm. It is needed for the propeller.
  • Clamp or any other device for attaching the device to the boat.
  • Welding machine.
  • Fixing elements.
  • Additional tools for work.

All necessary elements can be bought or made by yourself. The drawing may be needed to design a homemade propeller, but not for the drive. The size of the propeller depends directly on the power of the drive, as well as the weight of the watercraft. For example, a screw with dimensions of 10×3 cm can move a vehicle weighing about 120 kg.

Instructions for making

To make a boat engine from an ordinary grass trimmer you will need to do the following steps:

    Never throw away or lose the nuts, because the companies developers use their own type of thread, which is not metric or inch

Redo the bent shaft. To do this, remove the original nut, which is located in the line reel. It looks like a small tube of 2cm in length and has an internal thread. It can be split into two large nuts. Tip! Never discard or lose the nuts, as the companies developers use their own type of thread, which is not metric or inch. Next, it is necessary to remove the plastic cover, which is located on the throttle button. At the end of the bent rod there are no roller bearings, instead there is an ordinary sleeve made of bronze, also known as a plain bearing, it must be removed. To do this you need to carefully cut it, first unscrew the nut and remove the metal and stern shaft from the tube. Once free of the bronze sleeve, you can proceed to knock out the tread of the flexible shaft, which is made of plastic. Tip! The steel pipe can be thrown away as it cannot be aligned. Instead of it we use duralumin tube with appropriate diameter. Insert the bronze sleeve in the duralumin tube and press it carefully into the tube with a hammer. Then take a plastic tread, cut it a little in diameter and fit it tightly into the tube. Tip! If the outer diameter of the tube is larger and does not fit into the mounting hole on the motor head, you need to turn it to the right size. If necessary, you can build a longer shaft using a tube of desired length, and install a steel bar instead of a flexible shaft of desired length.

For the running-in of the homemade engine you will need a tank of gasoline (0.5 l.) with oil at a ratio of 1:40. One fuel tank gives you a range of about 10 kilometres. The speed of the vehicle with such a motor is in the range from 5,6 to 7,9 km / h, depending on the load of the boat.

grass, trimmer, conversion, boat

How to make a boat motor with their own hands from a grass trimmer?

To make a boat motor from a grass trimmer can be independently.

This requires the following set of tools:

  • Grass trimmer, acting as the basis for the creation of the future boat. For a small boat, it is recommended to create a design with a power of 0.8 kW. Even this figure is enough to achieve a speed of about 5-7 km/h. If the motor is created for a massive and heavy boat, you should choose a more powerful grass trimmer.
  • The screw in most cases is made of duralumin, which thickness is about 2 mm. Such material is able to serve for a long period and no corrosion is formed on the surface.
  • Metal work also requires a vise, which allows you to fix the material on its treatment.
  • A welding machine is required to connect the individual elements. It is best to use a semi-automatic version, since when you use it, even if you do not have the proper experience, you can get a quality connection.

The production of this product can not be called a simple process, but it is still feasible at home.

The instructions are as follows:

  • Prepare projects regarding the manufacture of the screw. It is almost impossible to make calculations by yourself.
  • The edges of the propeller are sharpened.
  • The blades are often made curved by 10 mm. In some cases the material is not bent, because it is characterized by a high degree of plasticity.
  • The screw is fixed in place of the grass trimmer head.
  • On the Internet you can find a large number of adapters designed to connect the motor to the propeller. They are cheap.

Note! The starter fits from a standard mower. If it is necessary to provide more convenient conditions for starting the engine, then a gear from an old bicycle is installed. Before direct use of the construction it is necessary to check all seams, as even minor cracks over time will cause serious defects.

Reviews

Considering the motor from the trimmer for grass, you should pay attention to the fact that the hum at the time of operation it will be strongly.

I installed a grass trimmer on a rubber boat. I did not expect that it will be so fast, so in the design you need to pay attention to power.

My friend has. He is generally happy with his motor, especially its economy, says he would not trade it for another.

My boat is very fast, all thanks to the motor from the weed trimmer. I made it myself, there were no problems, but I had to use a lot of readymade parts.

Grass trimmer is a lightweight motor for the boat. Due to its high efficiency and power it is very popular.

Motor for a boat with their own hands

You can make a homemade boat motor from a trimmer for grass. First you should prepare the materials and tools:

  • Grass trimmer with a capacity of 3 liters.с.;
  • 2 mm thick steel plate for the screw;
  • Welding machine;
  • mounting;
  • a clamp to mount the motor on the side of the boat;
  • angle grinder;
  • drill.

Before the work, you need to create drawings with all the dimensions, necessary parts and assemblies for the work, as well as the scheme and order of installation.

grass, trimmer, conversion, boat

Need to figure out the size of the propeller, which depends on the power and weight of the boat with the load. It should be taken into account that a propeller with dimensions 3×10 cm, mounted on the engine, can carry a boat with passengers with a total weight of up to 120 kg.

Stages of work on making a motor from a gasoline mower:

  • To make a motor for a boat, first you need to remake the bent shaft.
  • Then make the propeller.
  • Replace the plastic motor cover with a switch.
  • Attach the shaft to the engine from the mower.

Modifying a bent shaft

First you need to remake the bent shaft. To do this, you need to take a nut 2 cm high in the form of a cylinder with a notch inside. Unscrewed nuts and bolts must be saved, as they have non-standard threads. Then redo the rod with the rigid shaft. Remove the flexible shaft from the boom by removing the nut.

The end of the rod has no bearings. a sleeve replaces them, so it must be cut out. Remove the tread. Since the metal pipe is bent, it is difficult to straighten it, so it will not be used. Replace it with a dural tube of the same diameter or smaller than the diameter of the sleeve.

Install the bronze bushing in the pipe. To do this you need to bore the tube slightly. Then carefully press the sleeve into the groove with a hammer. In doing so, do not force the sleeve so that it does not deteriorate. The tread is cut to the desired diameter and placed in the rod. If the tube has a large diameter and it is difficult to fit it into the ICE head hole, it is necessary to grind it to the required size.

Take a steel rod instead of a flexible shaft and connect it to the motor shaft. Then screw the propeller on the shaft and secure it with a nut. Then you need to fix the rod with inner shaft to the engine by means of adapters. They need to be made in a lathe workshop. Different models of mowers may have peculiarities that must be taken into account.

Using the gearbox from the angle grinder

To create a boat engine on the basis of a haymower often use a gearbox from an angle grinder. It needs to be modified. The shaft with the gear must be replaced with a longer one, which will correspond to the rod. The end of the shaft is made similar to the extracted short shaft, so that the same bearings can be used.

In the places where the bearing is installed, mount the gland, which will protect the bevel gear from water. The gearbox housing is twisted with sealant. Grease is poured into the gearbox to cover the gears.

Making a screw

To make the screw you need a 100 mm long and 30 mm wide strip of duralumin. If you put the propeller on the table, then from it to the blade should be 10 mm. The angle of the propeller blades must be adjusted with pliers. Before this, perform annealing of dural. You can make propellers with 2 or 3 blades, different sizes. The dimensions of the propeller should be selected individually.

Features of a homemade engine

When converting a motor, it is worth bearing in mind that they were designed to perform different functions. Grass trimmer functions at high revolutions and low torque, and a boat motor should do the opposite. Therefore, remaking the device requires special tools and even a drawing.

The engine of the trimmer for grass to build more convenient and easier, as it has a number of necessary component mechanisms:

  • a very economical engine;
  • an integrated unpainted fuel tank that allows easy control of the fuel quantity;
  • The presence of a starter and gas in the device;
  • A boom equipped with a rigid shaft.
grass, trimmer, conversion, boat

It remains only to buy the missing parts or make them yourself and you can proceed to the manufacture of the engine for the boat.

Grass trimmer functions at high revolutions and a small torque, and the boat motor should do the opposite

What you can do

There are several options for fine-tuning the grass trimmer under the motor for the swimmer.

Take as a rule, on every fishing trip, the first thing to start.

A very simple method, but requires additional financial expenses.

It will be necessary to purchase such parts:

  • Clamp for attaching the device to the boat transom.
  • Propeller. You can buy a ready-made set through the Internet, because in stores such products may not be. Includes a special drive, made of stainless steel, as well as universal adapters for flexible shaft trimmer for the grass, which allows not to bother with the fact that they fit to your model of lawnmower or not.

The drawing of the attachment to the trimmer is shown in the manual. For installation it takes about half an hour.

For trimming you will need the angle reducer from the angle grinder, a screw, which can be cut from a sheet of stainless steel, as well as seals and bearings for the fasteners. This way to get the maximum rpm despite the small pitch of the propeller. In the field, the device requires additional adjustment, which is done with a pair of pliers.

This method is performed as much as possible with your own hands. Let’s take a closer look at a lawnmower with a two-stroke motor with 25 cm3. The 700 W unit weighs 4.5 kg and has a bent leg. the grass trimmer with such power allows the boat to move at a speed of about 5-7 km/h.

For modification you will need an angle gearbox from an angle grinder, a propeller that can be cut from a sheet of stainless steel, as well as seals and bearings for the fasteners

What you need

For the manufacture will require materials, as well as tools:

  • Grass trimmer.
  • Duralumin with a thickness of 2 mm. It is necessary for the propeller.
  • Clamp or any other device for fixing the device to the boat.
  • Welding machine.
  • Fixing elements.
  • Additional tools for work.

All of the necessary elements can be purchased or made by yourself. A blueprint may be needed to design a homemade screw, but not for the drive. The size of the propeller depends directly on the drive power as well as the weight of the swimmer. For example, a propeller with dimensions of 10×3 cm can move a vehicle weighing about 120 kg.

Fabrication instructions

To make a boat engine from an ordinary grass trimmer you will need to do the following steps:

Under no circumstances throw away or lose the nuts, because the developers use their own type of thread, which is not metric or inch

Rebuild a bent shaft. To do this, remove the nut, which is located in the bobbin with a fishing line. It looks like a small tube of 2cm in length and is threaded on the inside. It can be split into two complete nuts. Tip! Never throw away or lose the nuts, as the developer companies use their own type of thread, which is not metric or inch. Next, it is necessary to remove the pad of plastic, which is located on the gas button. There are no roller bearings at the end of the bent rod, instead there is a plain bronze sleeve, also known as a plain bearing, it must be removed. To do this, you will need to carefully cut it out by first unscrewing the nut and removing the metal and stern shaft from the tube. Once you are free of the bronze sleeve you can now proceed to knock out the tread of the flexible shaft, which is made of plastic. Tip! The steel pipe can be thrown away as it cannot be aligned. Instead of it, we use a duralumin tube with the appropriate diameter. Fit the bronze sleeve into the duralumin tube and press it carefully along the spindle with a hammer. Then take a plastic protector, cut it a little in diameter and mount it tightly in the tube. Tip! When the outer diameter of the tube is larger and does not fit into the mounting hole on the motor head, you will need to mill it to the right size. If necessary, you can build a longer shaft using a tube of desired length, and install a steel bar instead of the flexible shaft of desired length.

  • Make a screw. For it, we use a duralumin strip with the dimensions of 10×3 cm and process it according to the drawing, then carefully sharpen the edges. The pitch of the screw should be about 10 mm, so each blade should be bent up 1 cm. For fixing, it is enough to use a nut. The dowel is not needed, in case the screw touches something, it will automatically stop the motor. easy to adjust with a pair of pliers. If the rpm created by the propeller is low, the blades may be shortened. Tip! Create a special ring attachment so that the screw does not accidentally hit the cylinders.
  • Gas sector. You can install an ordinary bicycle gear shift on the hull instead of the original plastic plate. If desired, you can change the course of the exhaust gases and direct them towards the propeller.
  • Fixing the shaft to the motor. You can use ordinary laminated plywood to make the two spacers needed to secure the motor to the head and use four screws to clamp the shaft properly. If necessary, the shaft can be disconnected at the time of transport of the unit.

Methods for making a boat motor from a brushcutter

The easiest way to make a motor for a watercraft is to use a brushcutter with a straight leg (boom) and, therefore, a rigid shaft. In that case all improvements are limited to the production of the propeller, which can be cut from a strip of stainless steel or duraluminium. The size of the workpiece. 100x30x2 mm. The blades should be given a curved shape, for which they need to be bent by about 10 mm. Edges of the propeller need to be sharpened. An example of a simple drawing of a propeller is shown on the picture below.

Important! The size, number of blades and angle of bend are chosen individually, based on the weight and size of the boat and the power of the engine trimmer for grass.

Place the manufactured propeller in place of the trimmer head. Herewith it is desirable to use a circular nozzle, which will not allow the propeller to damage the boat. The process of grass trimmer revision with your own hands is shown in more detail on

Updating the gearbox of the angle grinder

To get the maximum engine speed, you can equip the grass trimmer with an angle reducer from an angle grinder, which must first be finalized. In this case you may need glands and bearings. The process of improving the gearbox itself is to replace the original short shaft with a longer one, corresponding to the size of the trimmer’s boom for grass. But this requires disassembly of the gearbox.

Important! Shape and mounting dimensions of the new shaft must match the parameters of the unit removed from the gearbox. This in turn allows the use of existing bearings and pinions in the gearbox.

After you have made the new shaft, reassemble the gearbox and protect the bearing with a watertight gasket beforehand. In addition, it is recommended to apply thick grease to the existing gears or fill the inner cavity of the housing with it. To seal the housing, use a rubber seal and/or sealant.

Back to Note! Increasing the trimmer engine speed through the gearbox, you should attach the propeller on the output shaft of the latter.

Finishing of grass trimmer with bent boom

If the owner of the boat has a lawnmower, which rod is bent, the latter must be dismantled and replaced with a straight tube of the appropriate diameter, made of duralumin. If the diameter of the new tube is larger than the size of the hole in the engine block, the seating will need to be turned down to the required size. Retrofitting is carried out in the following order (see Pic. drawing).

  • First unscrew the original nut 2, which is located in the bobbin with cord. Do not throw out the fasteners removed from the rods, because brushcutter manufacturers often use their own threaded fasteners that do not fit the standard specifications.
  • Then unscrew original nut 4 and remove the stern tube (pos. 8) and flexible (pos.9) shafts.
  • Then cut out position 6. sliding bearing (has a bronze sleeve at the end of the shaft).
  • Next knock out of the rod plastic protector 10.
  • Into a selected beforehand straight pipe 7 press the previously extracted plain bearing 6. It may be necessary to bore out the tube for this.
  • Then the sliding bearing 6 is carefully pressed with a hammer on the groove 5. Here it is important not to damage the pressed bronze bush.
  • Then the plastic tread 10 is trimmed in place and firmly inserted into the tube 7.
  • Next, the deadwood shaft is connected to a steel bar, which will replace the flexible shaft 9. The help of a turner may be needed for this.
  • The final step. the propeller 3 is attached to the stern shaft 8 with a nut 2.

Assembled boom is connected to the motor with the help of specially made adapters, whose shape and size depend on the design features of a particular model of grass trimmer.

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How to properly use a boat motor from a brushcutter?

Using the trimmer for grass, as a boat motor, the operator must constantly monitor the condition of the engine, and give him time to cool down.

In addition, to extend the life of the boat motor from the grass trimmer will help:

  • Checking all the available in the device fasteners. before each start of the engine, you need to carefully inspect the locks that hold the elements of the engine from the grass trimmer;
  • filling the engine from the grass trimmer only with the gasoline and oil that was used to operate the brushcutter;
  • timely cleaning and replacement of the engine air and fuel filter;
  • Regular inspection and timely replacement of the fuel pump;
  • Inspection and, if necessary, replacement of the spark plug.

To extend the life of the boat engine from the grass trimmer, regular ventilation of its regular cylinder will also help. For this purpose, approximately every 2 months you need to unscrew the spark plug, and 4-5 times rarely pull the starter rope. After the procedure, the spark plug can be screwed back in place and continue operating the engine.

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How to make a boat motor with their own hands from a trimmer for grass?

To create a boat motor from a lawnmower is suitable tool with a straight rod. If the grass trimmer boom is curved. you will have to work on its improvement.

The modification is done according to this algorithm:

    First remove the original nut (marked with number 2 in the drawing below). Do not throw it away or lose it, as it is impossible to replace the factory parts with ordinary nuts.

If it is not possible to purchase a ready-made conversion kit as mentioned earlier, the adjustment handle can be taken from a sport bike handle.

You can also make a screw yourself from a piece of duralumin using the drawing below:

The pitch is the distance from the blade to the horizontal surface. Adjust the angle with a pair of pliers. To do this, preheat the workpiece.

To fill the motor from the grass trimmer on the boat, use only high-quality fuel and lubricants. Dilute gasoline with oil in the appropriate proportion. Do not expose the engine to high loads for the first 10 kilometers. this will be the break-in period. Depending on engine power the boat with such a motor can reach a speed of 5 to 8 km/h.

Below is a video, which demonstrates the work of such a unit:

Making the fastener to mount the motor to the boat

To install a homemade boat motor from a lawnmower, you can use a ready-made clamp. But if you have an old manual meat grinder in the garage, it will not be too difficult to make a mount for the motor, with which it can be mounted on the transom:

  • Use an angle grinder to cut out the bottom of the meat grinder and drill a hole with a diameter of 12 mm in the transverse plane of the hull.
  • Flatten one end of the rod with cross section diameter of 12 mm and length of 100 mm and drill a hole with diameter of 6 mm in the resulting plane.
  • Insert into the resulting hole a bolt with a suitable cross-sectional diameter. The ring of the grass trimmer will be put on it, originally designed to attach the belt.
  • Now you can connect the homemade mount to the boat transom with a stud and a nut. Install the motor and secure it with the appropriate nut.

Motor for a boat with his own hands

It is possible to perform a homemade boat motor from a grass trimmer. First you should prepare materials and tools:

  • Grass trimmer with a capacity of 3 liters.с.;
  • 2 mm thick steel plate for the propeller;
  • welding machine;
  • mounts;
  • a screw clamp for mounting the engine on the boat;
  • Angle grinder;
  • drill.

Before the work, you need to create drawings with all the dimensions, necessary for the work of parts and components, as well as the scheme and order of installation.

Find out the size of the propeller, which depends on the power and weight of the boat with the load. It should be borne in mind that the propeller size 3×10 cm, mounted on the engine, can carry a boat with passengers with a total weight of up to 120 kg.

Stages of work to make a motor from a gasoline mower:

  • To make a motor for a boat, you must first redo the bent shaft.
  • Then make the propeller.
  • Replace the plastic engine cover with a switch.
  • Attach the shaft to the motor from the mower.

Rebuild the bent shaft

First you need to redo the bent shaft. To do this, you need to take a 2 cm high cylinder shaped nut with a notch inside. Unscrewed nuts and bolts must be kept because they have non-standard threads. Then redo the boom with a rigid shaft. Extract the flexible shaft from the bar by removing the nut.

The end of the boom has no bearings, a sleeve replaces them, so it must be cut out. Remove the tread. Since the metal pipe is bent, it is difficult to straighten it, so it will not be used. It must be replaced by a dural tube of the same diameter or smaller than the diameter of the sleeve.

Place the bronze sleeve in the tube. To do this you need to bore the tube slightly. Then gently tap the bushing into the groove with a hammer. It is not advisable to use force in order to prevent the bushing from becoming damaged. The tread is cut to the correct diameter and placed in the boom. If the tube has a large diameter and it is difficult to fit it into the hole in the cylinder head, you need to grind it to the required size.

Instead of a flexible shaft, take a steel bar and connect it to the motor shaft. Then you need to screw a screw on the shaft and secure it with a nut. Then fix the rod with its inner shaft to the motor using adapters. They should be made in a lathe workshop. Different models of mowers may have peculiarities that must be taken into account.

Using the reducer from an angle grinder

To create a boat engine on the basis of a haymower often use the gearbox from an angle grinder. It must be finalized. The shaft with the pinion must be replaced with a longer one, which will fit the rod. The end of the shaft is made similar to the extracted short shaft, so that the same bearings can be applied.

In the places where the bearing is installed, an oil seal is mounted, which will protect the angular reducer from water ingress. The gearbox housing is screwed together with sealant. Pour grease into the gearbox to cover the gears.

Propeller making

To make the propeller need dural strip length 100 mm and width of 30 mm. If I put the propeller on the table it should be 10mm from the propeller to the blade. You need to adjust the angle of the propeller blades with the pliers. Anneal the dural before making the propeller. You can make propellers with 2 or 3 blades, different sizes. Propeller dimensions should be chosen individually.

Hunting and Fishing Community Blog About the boat motor

Good afternoon fellow anglers! Found and internet is a miracle! The construction is not complicated but there are a lot of questions. Maybe someone uses it and can share their experiences. And another question: should this device be registered in Belarus as a boat motor? Thank you all!

Комментарии и мнения владельцев 41

A leg from the wind with a propeller, plus a four-stroke engine with five horsepower and you’ll be happy!

And at what rpm does it have power?? On the screw to 2500 at rated should get. Than lowering it? What’s the torque rating?? The closer to a diesel motor, the better. In general, I assume that this is all bullshit.

I support those who are against this miracle motor.It is better to be patient and to buy normal, minimum 5 hp, or better 15 hp (if the boat will allow)

I work in a gardening service. They used to haul Chinese boat motors in the summer, but there was a lot of noise. I met this device, a good thing, though air cooling is not a problem, if you look at the summer in the city maintenance workers are running around with trimmers all day mowing and nothing boils and the motors do not break. This motor has three.8 force, if someone in the garden is a simple gasoline trimmer you can buy a simple boot and operate the same way (I found the boot at a price of 8,500rub.) it’s enough on small rivers. You should not expect anything more. Contacted the service and talked to a mechanic who services these motors. Surprisingly I have not heard anything bad from him. The price of such a motor is 11 500rub. Now going to buy an acquaintance this motor and will test in practice. Good luck to all

I have a nozzle for a STIHL chainsaw under the ice drill.I use it sometimes at the end of the winter. You know, I’m satisfied))))! When only I started to join the water-powered hobby, I also considered buying a similar device for a boat motor and reviewed a bunch of options, but in the end, I still took the scooter for 2.5 л.с. And then, the race to “armaments”, has done its work.After 3 years, already Yamaha 15 and the boat is bigger ). If you do decide to buy, waiting for reports )))).

Wasted money because the cooling air. It’s not a rush to get this stuff floating. and in the heat, 32 in the sun, moments boil over. Better to get a second hand motor or a new Chinese one. I took a HDX 4 forces) happy to shit

Money well spent. Buy a normal motor.

It’s made pretty well, starts up without a problem. Economical, convenient “automatic transmission”. Of the disadvantages. it roars so that I temporarily lost hearing in one ear. It is not possible to make it any quieter. The speed on my boat is about 8 km / h. Very noisy gearbox, or clutch mechanism as heated, when the collapse did not know, passed 10-20 km. Live photos are here: www.drive2.ru/l/4062789/

Oh, man! cool! I liked it with the fin. and the Комментарии и мнения владельцев there are a load of crap

found this miracle on a paddle faster though, the chainsaw only pulls gasoline ))))

I just heard the guys took such tools for STIHL chain saws.But, it’s not my thing

grass, trimmer, conversion, boat

Noise from it All the fisheries inspectors are gonna be all over it!

I myself have dealt with a similar issue, so neither this nor the 2.5 horsepower, start with 5 horses at least

I saw a guy on a PVC boat with this, he passed me in five meters, I almost went deaf and the fish after him went somewhere.

No, this miracle is not worth taking, a friend had a rare, loud and shit does not go!Koresh sold it in a week and bought himself a Chinese Yamarin motor.

The engine is from a lawn mower. I’ve got a grass mower like that.3hp.on the passport. I think it’s possible to put it on a light rubber band. but there is a cooler one !(

) watch out I’ve been sick for three days.

I read the Комментарии и мнения владельцев on the video even more fun.

well there are so many options you can think of, cut off a cow’s leg and as long as the reflex can swim))

lawnmower engine. I have a grasshopper 3.3hp.according to the passport. on a lightweight rubber band, you can probably put it on. but there’s something cooler !(

) watch out I’ve been wiggling for three days.

the engine from the lawnmower. I have such a scythe for grass 3.3c.according to the passport. on a light rubber, maybe you can put it on. but there’s a better one !(

) watch out I couldn’t get over it for three days.

Thanks!I did not expect such a cool idea. our ingenuity we are unbeatable!I haven’t laughed so hard in a long time!

The engine’s from a lawn mower. I have a grass mower like this 3.3 hp.engine. You could probably put it on a lightweight rubber band. but there’s a tougher one !(

) Watch out I couldn’t come to my senses for three days.

The engine from the lawnmower. i have a grass trimmer 3.3hp.according to the passport. I could probably put it on a light rubber. but there’s a cooler thing !(

) watch out I’ve been sick for three days.

The engine’s from a lawnmower. I have a grasshopper 3.3hp.according to the passport. You can probably put it on a lightweight rubber. but there’s something cooler !(

) watch out I could not come to my senses for three days.

Website gardentool.under gasoline grass trimmers.

I saw a man floating on a rubber band once. That’s funny. Only as a helicopter should be taken into account!