Making a homemade outboard motor of chainsaw

Recently, fishing enthusiasts are increasingly attracted by the opportunity to independently make a homemade outboard motor from chainsaws. The existing diversity on the market, offering to purchase a boat motor, allows you to choose from a wide range of models and manufacturers. To equip your boat with a suitable engine will not be a big problem. If it were not for one “but” - the price, which is often not available for most average people, especially those living in rural areas.


You can easily make an outboard motor out of a chainsaw and it will be cheaper than buying a motor in a store.

Of course, to move around the reservoir, you can use the method, old as the world, rowing with oars. But how far will you swim in this way? And my hands are busy all the time, in suspense - what a pleasure it is to hunt fish ... And here comes the thought of the advantages of a boat motor. After thinking a bit and checking the budget, many decide to make the motor themselves, using the available tools and mechanisms. Especially if at least minimal technical skills are available.

Features of the outboard motor of chainsaw

From a convenient tool for sawing wood, chainsaws, you can build almost anything, making some very minor changes to its design. Making an outboard motor will require little intervention and will retain the basic function of the tool quite usable. But you have to choose: either a good saw, or quite a good engine, albeit a thin one. And if we recall the price of the factory outboard motor approximated in power, it becomes clear that making homemade products will cost almost three times cheaper.

Gearbox motor with modified deadwood

Gearbox motor with modified deadwood: a - gearbox housing, b - stud with nut, d - reverse pull, e - modified deadwood; 5 - screw shaft.

Of course, you should not buy a chainsaw specifically in order to convert it into a motor for a boat. In this case, it is really better to purchase ready-made motors, specially designed for operation both in calm water conditions and along a fairly strong current. It is safer and more relaxed.

But the happy owners of "Friendship", "Calm" or other modifications may well be engaged in the modernization of the tool. Especially with free time, certain skills and the necessary tools and equipment.

It is better, of course, to use the models of chainsaws of German manufacturers, which have great power.

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Preparatory work

So, to make a homemade outboard motor out of a chainsaw, you will need:

  • chainsaw;
  • reducer from unnecessary grinder, transmission oil;
  • screw (lying around from the old motor or self-made);
  • transom (if not in the configuration);
  • clamp for fastening.

Of the aids useful:

  • a lathe (ideally, although you still cannot make various parts with available tools);
  • ruler, caliper;
  • steel pigs;
  • blanks from the corner;
  • fasteners.
Mounting the motor of a chainsaw to the boat

The motor is recommended to mount on the boat so that the propeller shaft at a small angle is immersed in water.

First of all, it is necessary to replace the base for the chain with a design with a screw, made by hand. At the same time, nothing is altered irrevocably; mechanisms are simply rearranged. Replacing one unit with another directly on the river bank will take very little time and will not reduce the hunting excitement.

First, the clutch is remade. The process is to carve a smaller cup and replace the spring. All these manipulations are performed in order to reduce the starting torque of the clutch and adjust the dimensions and weight of the structure to more suitable parameters.

For example, if there are bearings of the roller type 941/12 and two pieces of 7000 CD, as well as a suitable shaft, a cup with an outer diameter of 78 mm and a thickness of about 16.5 mm is quite suitable. The plane of contact between the coupling bowl facing the engine and the sides of each sector is approximately 3 mm greater than their thickness (in a particular case approaches 14 mm), the remaining space above the movable part of the 4 mm coupling is quite enough. In a set of such a cup with the specified type of roller bearing, the clutch is even quite good. It is necessary to provide and grooves for brackets, three is enough. Staples are made of a corner with a side of 25 millimeters, one side of them has a trapezoidal shape. The bowl and the lid of the coupling are connected by brackets, which are clamped with a screw with a washer. With the screw with the strap, the pin connecting the shaft and the coupling cup is covered.

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Assembly unit assembly

Trimmer outboard motor scheme

The scheme of the boat motor trimmer.

The assembled construction height is barely 10 cm (taking into account the body, the protective screen, including the distance to the support plate). The distance between the axes of the studs in this case will be 32 millimeters with a height of 24.5, the center distance from the shaft to the first stud will be 54 millimeters. Considering that the weight of the whole structure (although without regard to the tire) is quite suitable, a little more than 4.5 kg, you can choose a pin with a metric thread with a diameter of 8 mm and a thread pitch of 1 mm for mounting.

Next is the connection of the shafts of the gearbox and the motor through the sector-key. "Leg" with the gearbox will give an additional 4-4.2 kilograms.

To fix the engine and the shaft, you will need a channel. Armed with a grinder, the mount of the desired configuration is cut out from the workpiece, and then holes are drilled for fasteners connecting the structure and the chainsaw itself.

When assembling it is necessary to take into account the sufficient distance between the front bowl of the coupling and the support frame. The gearbox, borrowed from the grinder, will be mounted on the second side of the shaft.

The next stage of work will be the design of the swivel unit. To do this, you will need a piece of tube with a diameter slightly larger than the shaft with a welded angle for attaching the guide, a hollow hexagonal guide, a metal rod suitable for the diameter and a billet of rectangular metal with holes in the ends to secure the rod, as well as a slot in the upper part for ease of operation.

The edges of the carved "handle" in the workpiece must be carefully cleaned. A guide is attached to the corner by welding, and then using the rod, the resulting structure is connected to a rectangular “handle”. At the ends of the rod, you can cut the threads for reliable fastening, you can simply install with a little tightness. Then the entire unit is mounted on the shaft and secured in a place convenient for management.

Well and, of course, before assembling the details, it is necessary to give an aesthetic appearance whenever possible, for which each of them is subjected to cleaning and painting.

In the next step, you will have to adapt the gearbox shaft for the available screw. This important detail is desirable, of course, to use ready-made, can be removed from the old motor. For those who are not looking for easy ways, the option of making homemade products is possible. In the image of a screw of factory origin, a mold is made into which the future screw is poured in using epoxy glue and glass fabric. After some simple manipulations (grinding, painting) the screw is ready. However, keep in mind that the propeller will take on a significant load, and in the manufacture it is very important to withstand all dimensions correctly. Therefore, it is better to use the finished part.

After the screw and the shaft of the gearbox are connected with a stud, the final stage begins. Transmission oil is poured into the gearbox, the lid together with the installed shaft is fixed using sealant. And then - the final assembly of the entire structure. For ease of use, you can still additionally mount the throttle.

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As a conclusion

So, having available tools, showing desire and perseverance, you can construct a homemade outboard motor, without resorting to special transformations of chainsaws. The output will be such a boat motor, pulling out about 3.3 hp. and allows you to reach speeds of up to 10 km / h. At the same time, he “eats” about a quarter of a liter for almost half an hour of movement, provided there is a small amount of cargo in the boat and two avid fishing enthusiasts.

For an inflatable vessel, such a motor is quite suitable, especially if there is no need to constantly work with an oar. Many "testers" are convinced that such a homemade product can be exploited up to six years, naturally, not too heavy. The operating conditions may also affect the duration of the work, and it is important that the chainsaws are of high quality, which already depends on the manufacturer.

If desired, a homemade outboard motor can be supplemented by exhaust exhaust to reduce noise, but this will negatively affect the main function of the chainsaw itself.

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