Boat motor from a lawnmower with their own hands

How to make a boat motor from a lawnmower

For the movement of a motorboat, the installation of a light mounted motor is often carried out. It is worth considering that such a mechanism is quite expensive and difficult to service.

Small boats are often equipped with trimmer motors. Today they are very popular, for equipping is carried out the purchase of a special attachment. Let us consider its features in more detail.

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

Motors for light boats are often made of grass trimmer.

The following can be called the main ones:

  • The clamp for the installation of a homemade construction with a trimmer on the prepared transom of the boat is very widespread. This option is considered more affordable, but is also characterized by increased efficiency in application. The special design allows the device to be used 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 widespread.
  • Propeller. This version of the execution is a little more complicated than the previous one, but there are ready-made mechanisms on sale, which are characterized by increased efficiency in the application. It is not recommended to carry out the most powerful version of the design, because due to the resulting draft a lightweight PVC boat can simply flip over. Often includes a special drive, made by using corrosion-resistant steel, as well as some adapters, which make the grass trimmer almost a universal boat motor.
  • Another common option is to convert 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 for operation. Relatively small weight, which is 4.5 kg, is a significant advantage of such a version.

Note! The operating principle of the construction should be taken into account when making your selection. The wrong grass trimmer will not last for a long period of time.

Working principle

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. Due to this, a high speed of moving the boat on water is ensured.

To the peculiarities of the principle of operation can include the following points:

  • blades turned outwards.
  • The motor installed in the upper part transmits the rotation to the blades.
  • In order to increase reliability, the shaft that connects the motor with the blades is located in a protective tube.

Note! The higher the position of the grass trimmer, the higher 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, as the noise can scare away all prey.

Advantages of using a grass trimmer

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

Let us name the following as the main ones:

  • Relatively low cost.
  • Easy assembly and disassembly.
  • Low weight.
  • The high speed achieved when driving.
  • High power factor, often excessive.
  • Economical.
  • Initially, there is a throttle handle and starter.
  • There is a special foot that allows you to adjust the power of the device.

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

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

Motors for lightweight boats are often made from a grass trimmer.

The following can be called the main ones:

  • The clamp for installing a self-made construction with a trimmer on the prepared boat transom is very widespread. Considered to be more affordable, but still offering high efficiency in application. Special design allows the use of the device as a propeller. 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 already on sale ready-made mechanisms which are characterized by a higher efficiency in the application. It is not recommended to carry out the most powerful version, because due to the resulting traction the lightweight PVC boat can simply tip over. Often includes a special drive, made by using corrosion-resistant steel, as well as some adapters, which make the grass trimmer almost a universal boat motor.
  • Another common option is to convert 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 considerable advantage of this design.

Note! When choosing, you should take into account the principle of operation of the design. The wrong grass trimmer will not be able to serve for a long period.

Operating principle

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

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

boat, motor, lawnmower, their, hands
  • The blades are reversed outwards.
  • The motor installed in the upper part transmits the rotation to the blades.
  • To increase reliability, the shaft that connects the motor to the blades is located in a protective tube.

Note! The higher the grass trimmer is, the higher 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, as the noise can scare away all prey.

Advantages of using a trimmer for grass

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

Let’s name the following as the main ones:

  • Relatively low cost.
  • Easy assembly and disassembly.
  • Low weight.
  • High speed achieved when driving.
  • High power factor, often excessive.
  • Economical.
  • Initially there is a gas handle and a starter.
  • There is a special foot that allows you to adjust the power of the device.

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

Chainsaw model

It is possible to assemble a model from a chainsaw if there is a ready-made deadwood. The model will also require a good stand. Independently make it out of a pipe is difficult. Screws are used most often of small size. However, in this case, much depends on the power of the chainsaw. The clamp is fixed directly behind the starter. To protect the device from water, a cover is used.

A long rod is used to secure the stand. It should be soldered in an upright 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.

Operating principle

Grass trimmer has a higher rotation speed of the blades, which makes it possible to move through the water at a 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 reversed and, at the same time, performs the function of the most economical motor.

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

Features of the homemade engine

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

The engine from the grass trimmer to construct is more convenient and easier, as it has a number of necessary constituent mechanisms:

  • Very economical motor;
  • an unpainted fuel tank, which allows you to control the amount of fuel easily;
  • The presence of a starter and gas in the device;
  • 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 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 possible options for modifying the grass trimmer under the motor for the watercraft.

Make it a rule that on every fishing trip, the first thing to do is to start.

A very simple method, but it requires additional financial expenses.

It will be necessary to buy such parts:

  • Clamp for attaching the unit to the boat transom.
  • Propeller. You can buy a ready-made kit over the Internet, since stores may not have such products. This package includes a special drive, made of stainless steel, as well as universal adapters for flexible shaft trimmer grass, which allows not to bother with the fact that they fit to your model or not lawnmower.

Advice! Sometimes the kit may include a clamp, so before you buy it, clarify what is included in the kit.

The drawing of the attachment to the trimmer is shown in the manual. Takes about half an hour to install.

For conversion you will need an angle gearbox from an angle grinder, a screw that can be cut from a sheet of stainless steel, as well as gaskets and bearings for the fasteners. This method allows you to get the maximum speed, despite the small pitch of the screw. In the field, the device requires additional adjustment, which is done with pliers.

This method is performed as much as possible with your own hands. Let’s see it in detail on a lawnmower with two-stroke motor of 25 cm3. The device weighs 4.5 kg and has a power of 700 W and 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 redesigning you will 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 the fasteners

What will be needed

Materials, as well as tools, will be needed for fabrication:

  • trimmer for grass.
  • Aluminum 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 propeller with dimensions of 10×3 cm can move a vehicle weighing about 120 kg.

boat, motor, lawnmower, their, hands

Instructions for making

To make a boat engine from an ordinary grass trimmer you will need to perform 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, you need to take out the castle nut, which is located on the fishing line spool. It looks like a small tube 2 cm long and has an internal thread. It can be separated into two complete nuts. Tip! Under no circumstances throw away or lose the nuts, because the developer companies use their own type of thread, which is not metric or inch. Next, you need to remove the plastic cover, which is located on the gas button. There are no roller bearings on 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, it is necessary to carefully cut it out by first unscrewing the nut and removing 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 tube can be discarded because it cannot be aligned. Instead of flexible shaft we use duralumin tube with the appropriate diameter. Fit a bronze sleeve into the duralumin tube and gently press it into the tube with a hammer. Then we take a plastic tread, trim it a little in diameter and fit it tightly into the pipe. Advice! When the outside 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 correct size. If necessary, you can build a longer shaft using a tube of desired length, and install a steel bar instead of flexible shaft of desired length.

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

Lawnmower modification

The boat motor from a grass trimmer requires little modification to get a working “horse” for the watercraft. The advantage of gasoline trimmers is a small price and repairability. Homemade motors for boats on the basis of a lawnmower have a built-in tank, shaft and gearbox. You can look for a special retrofit kit, which will have a propeller and drive made of stainless steel, as well as a set of adapters to the shaft of the grass trimmer. Often there are kits with a clamp for mounting on the transom, so there will be no problems with attaching to the boat. If you act on the included instructions, you can make a boat motor out of a lawnmower in 20-30 min.

The fisherman will need more skills, if he decides to radically change the design of the trimmer for grass. In this case there is a huge room for imagination and ingenuity. One of the options is to make a vertical leg.

  • To rotate the shaft by 90 degrees in relation to the engine, you will need a reducer from an angle grinder.
  • The existing grass trimmer tube must be shortened with a cut-off machine. It is better to replace the bushings inside with bearings.

To fix the bearings inside the tube, it is necessary to make a careful crimping with a hammer on the circumference.

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Advantages and peculiarities of converting the grass trimmer into a boat motor

Using a lawn mower on the farm has a number of advantages. First, the boat owner will not overpay for a store-bought, expensive motor. Secondly, a motor for a boat from a brushcutter consumes much less fuel than a specialized boat engine. Third, a lawn mower motor is an order of magnitude smaller than a store-bought boat motor. There are a number of other factors that make fishermen use the grass trimmer instead of the boat motor.

  • The high reliability of modern trimmer engines;
  • complete tightness inside the hull;
  • Availability of all elements necessary to control the homemade engine;
  • built-in tank.
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Thanks to all these factors, the boat motor from a brushcutter is the most popular among enthusiasts.

In the process of recycling an engine from a lawnmower into a boat motor, it is extremely important to take into account that this power unit was produced for other purposes. Engines on trimmers operate at low torques, but, at quite high revolutions. In the case of a specialized boat engine, everything is the opposite. In this regard, to remake a motor from a trimmer for grass will need to prepare drawings, equipment and follow a certain order of action.

Despite some difficulties in the remaking, it is the trimmer that contains all the parts necessary for making a boat motor. a built-in starter and throttle lever, a boom with a rigid shaft and a semi-transparent fuel tank.

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Getting ready for work: the required technical basis

To convert a chainsaw to a motor for a boat, will come in handy:

  • Gasoline saw. in the described example it is “STIHL” MS 180;
  • reducer;
  • screw mechanism, which can be made by yourself or removed from a strictly motor;
  • lathe;
  • gauges;
  • metal corner;
  • angle grinder and an electric drill;
  • mounts.

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Stage of preparation for assembly

In order to proceed to the assembly of a boat motor from a chainsaw, you will need the following tools and devices:

  • Naturally, you will need the chainsaw itself.
  • The second necessary thing. a gearbox from an angle grinder, as well as gear oil.
  • A propeller is indispensable. You can take it from an old boat motor or make it yourself.
  • You will also need a transom.
  • To fix the construction you will need a clamp.

This is a list of basic tools, without which the assembly of a homemade outboard boat motor would be impossible. There are also a number of auxiliary devices that are recommended to have on hand to make the work easier:

  • You need a lathe, as you may not be able to make all parts by hand.
  • Ruler and caliper will be needed for easy measurements.
  • Materials you will need are steel blanks.
  • Parts for mounting and preformed angles.

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Complete set of nozzles

Now they sell special attachments for converting grass trimmer into a boat motor. Such a set includes everything you need for attaching it to your petrol mower motor. Control handle and push button switch are mounted to the boom. Gas handle is made with the possibility of switching speeds and equipped with a ratchet, which fixes the desired position.

The kit includes a fixture for mounting the unit to the boat. Grass trimmer attachment is easy to assemble and has a simple design. To assemble it is necessary to connect the gas cable to the motor, and then fix the muffler cable. The tool costs about 5 thousand rubles in a specialized store. rubles.

Motor for the boat from a grass trimmer

The idea of a lightweight outboard motor for a small boat, including a rubber boat, interests many fishermen and not only. Motor, which could be an alternative to the electric motor with heavy and not cheap batteries and a small power reserve plus no possibility of recharging in nature, for many dream. If to add rather low price and universality, there is a possibility to use in other useful purposes. then the motor trimmer for the grass (brush cutters or lawn mower. call it as you want). very bad variant. And if you already have a grass trimmer, it would be nice to use it as a boat motor. Why trimmer for grass? A lightweight, modern, “low-drinking”, with a built-in tank motor, with ready-made controls: throttle knob, starter. There is even a long “leg”, what more is needed?

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

The first and easiest, though not the cheapest, is to buy the necessary parts.

boat, motor, lawnmower, their, hands

Although you do not need to buy ready-made, you can make it yourself. A little imagination and a straight hand.

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

To create a boat motor from a lawn trimmer, a tool with a straight bar will do. If the grass trimmer boom is curved. you will have to work on improving it.

Remodeling takes place according to the following algorithm:

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

If it is not possible to buy a ready-made set for modification, which was mentioned earlier, the adjustment handle can be taken from a sport bike handle.

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

Pitch is the distance from the blade to the horizontal surface. Adjust the angle with a pair of pliers. For this purpose, the billet is preheated.

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

Below is a video that demonstrates the operation of such a unit:

Making a mount for mounting the motor on the boat

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

  • With an angle grinder cut out the bottom of the meat grinder and drill a hole with a diameter of 12 mm in the transverse plane of the housing.
  • The stud with a diameter of 12 mm and a length of 100 mm to flatten one end and drill a hole with a 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, originally designed for attaching a belt, will be put on it.
  • Now you can connect the homemade mount to the transom of the boat with a stud and a nut. Install the motor and secure it with the appropriate nut.

A motor for a boat with your own hands

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

  • 3 hp grass trimmer.с.;
  • 2 mm thick steel plate for the screw;
  • welding machine;
  • fasteners;
  • clamp for mounting the engine on the boat
  • angle grinder;
  • drill.

Before starting work, you should draw drawings with all the required dimensions, parts and assemblies, as well as a diagram and mounting sequence.

boat, motor, lawnmower, their, hands

You need to figure out the size of the propeller, which depends on the power and weight of the boat with the load. You must take into account that a propeller size 3×10 cm, mounted on the engine, can transport 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 a screw.
  • Replace the plastic motor cover with a switch.
  • Attach the shaft to the motor from the mower.

Redesigning the bent shaft

First you need to modify the bent shaft. To do this, you need to take a nut with a height of 2 cm in the form of a cylinder with a notch inside. Unscrewed nuts and bolts must be kept, because they have non-standard thread. Then redo the boom with a rigid shaft. Pull the flexible shaft out of the rod by removing the nut.

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

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The bronze bushing is inserted into the tube. To do this, you need to slightly bore the tube. Then gently tap the bushing into the groove with a hammer. At the same time it is not recommended to apply force so that the sleeve is not spoiled. Cut the tread to the desired diameter and place it 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 bar instead of a flexible shaft and connect it to the motor shaft. Then screw on the shaft and secure it with a nut. Then you need to fix the rod with the inner shaft to the engine with adapters. These need to be made in a lathe workshop. Different mower models may have special features that need to be taken into account.

Using the gearbox from the angle grinder

To build a boat engine on the basis of a haymaker often use the reducer from an angle grinder. It needs to be reworked. The shaft with pinion must be replaced with a longer one, which will fit the boom. The end of the shaft is made similar to the extracted short shaft to be able to use the same bearings.

In the places where the bearing is installed, mount an oil seal, which will protect the angle reducer from water ingress. The gear case is screwed together using sealant. Pour grease into the gearbox to coat the gears.

Making the propeller

To build the propeller you need a dural strip 100 mm long and 30 mm wide. If you put the propeller on the table, from it to the blade should be 10 mm. The angle of the propeller blades should be adjusted with the pliers. Before that, the dural is annealed. It is possible to produce the propellers with 2 or 3 blades of different sizes. The dimensions of the propeller should be selected individually.

Hunting and Fishing Community Blog About the boat motor

Good afternoon, fellow anglers! Found this miracle on the web! The design is not complicated but there are a lot of questions. Can someone use it and can share their experiences. And another question: is it necessary to register this device in the RB as a boat motor. Thank you all!

Комментарии и мнения владельцев 41

Korotch. a leg from the wind with a propeller plus a 4-stroke engine with five kobyls and you’ll be happy!

And at what rpm it has power? On the propeller to 2500 at the nominal should get. Than to lower? And what is its torque characteristic?? To a boat motor the closer to a diesel the better. In general, I believe that this is all bullshit.

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

I work in the service on a garden. I used to haul Chinese boat motors in the summer, only the noise was worth it. I met this device, the thing is good, 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 a 3.8 power, if someone in the garden has a simple gasoline trimmer you can buy a simple boot and operate in the same way (I found a boot at a price of 8,500rub.) that’s enough for the smaller rivers. do not expect anything more. Contacted the service and talked to a mechanic who services these motors. Surprisingly bad feedback from him I have not heard. the price of this motor is 11 500 rubles. Now going to buy my friend this motor and in practice we will check out. good luck to all

I have an attachment for a STIHL chainsaw under the ice drill.I use it sometimes at the end of the winter. You know, I am satisfied)))! When I first joined the water-powered hobby, also considered buying the same device for a boat motor and reviewed a bunch of options, but in the end, nevertheless took the scooter for 2.5 л.с. Well, then, the race “arms”, did its job.After 3 years, already a Yamaha 15, and a bigger boat). If you do decide to buy, waiting for reports )))).

Wasted money because the engine is air cooled. This thing sails slow. and in the heat, 32 in the sun, it’ll boil over. Better to buy a second hand motor or a new Chinese one. I got a HDX 4 forces) glad to shit

Wasted money. Get a proper motor.

Made pretty good quality, starts up without a problem. Economical, convenient “automatic transmission”. Of the disadvantages. it roars so that I temporarily lost hearing in one ear. No way to make it quieter. Speed on my boat is about 8 km/h. Very noisy gearbox, or clutch mechanism as it gets hot, when it will fall apart don’t know, ran 10-20 km. Pictures are here: www.drive2.ru/l/4062789/

Oh, man! class! I like it with the fin. and the commentary on it is a load of crap

Found this miracle on the oars is faster however, gasoline only pulls ))))

I just heard the guys took such nozzles for a STIHL chainsaw.but, it’s not my thing

The noise from it All the fisheries inspectors are going to pile in!

myself was engaged in a similar issue, so neither this nor the 2.5 horsepower is not advised, start with 5 horses at least

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

you should not buy this thing, it is too loud and does not ride at all!Koresh sold in a week and bought a Chinese motor Yamarin.

The engine is from a lawn mower. I have a grass mower like this 3.3 hp.according to the passport. You can probably put it on a light rubber. but there’s something cooler !(

I couldn’t get out of my mind for three days.

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

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

The engine is from a lawnmower. I have one for grass 3.3c.on the passport. You can probably put it on a lightweight rubber band. but there’s a cooler one !(

) Look out, I couldn’t stop laughing for three days.

The engine is from a lawn mower. I have a grass mower like that.3hp.according to the passport. on a lightweight rubber band you can probably put. but there’s a cooler one !(

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

Thanks!I didn’t expect such a cool idea. Our smarts are unbeatable!I haven’t laughed so hard in a long time!

A lawn mower engine. I got a 3hp grass mower like this.3c.on the passport. You could probably put it on a lightweight rubber band. but there’s a cooler thing !(

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

Lawn mower engine. I have a grass mower like this 3.3hp.by passport. ♪ on a lightweight rubber band, you can probably put it ♪. But there’s a cooler thing !(

) look out, I couldn’t get my head around it for three days.

A lawn mower engine. I have a grass mower like this 3.3hp.on the passport. I think you can put it on a light rubber. But there’s something a little cooler !(

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

Website gardentool.In the section petrol grass trimmers.

Seen once a man on a rubber band sailed. Funny. Put it on the books only as a helicopter!