DIY Chinese boat motor repair

In detail: do-it-yourself repair of a Chinese outboard motor from a real master for the site my.housecope.com.

This topic is perhaps one of the most relevant today, which is quite understandable. Long gone are the days when mainly domestic "Neptunes" and "Whirlwinds" roamed the water, and the appearance of spare parts laid out on the shore and repairs carried out, as they say, "on the knee" were perceived as the norm of life. Now a similar picture can be observed mainly in the outback. The situation has changed dramatically. The market offers the Russian consumer an almost full range of the latest water-motor equipment from abroad. The availability of engines from the world's leading manufacturers raises a number of questions, and our task is to understand them.

The first question and, perhaps, the main one, which, unfortunately, for most motor owners simply does not arise: how to choose the right propeller? This does not directly apply to engine repair, but it is extremely important to ensure the most favorable operating conditions for the engine as a whole and increase its resource. In other words, a correctly selected screw can reduce the likelihood of a malfunction, and therefore avoid the repair itself. The fact is that any outboard or stationary engine has a certain rpm range, in which it will develop maximum power and at the same time have optimal fuel consumption. Going beyond this range in one direction or another leads to a decrease in engine performance and an increase in fuel consumption.

There are a number of motors, the connection of tachometers to which is not structurally provided. In this case, when carrying out the test, it is necessary to use special tachometers that allow reading information from high-voltage spark plug wires. And to do this, you will have to again contact a service center equipped with a similar tool. And one more note: the standard propellers that come with the motor are usually matched exactly according to the results of such a test, but remember that your equipment (motor, propeller, boat, load) may become an exception to the rule.

Video (click to play).

Suppose that by selecting the propeller we have created the conditions for the engine for normal operation. But technique is technique, and breakdowns are still possible. True, there is a difference between breakage and breakdown. Therefore, let's try to figure out how to behave in a given situation. We will immediately exclude the option when the life and health of people depend on the performance of the motor - any interventions are permissible here. We will only consider the issues of current repairs.

It turns out that even a normally running motor requires periodic maintenance. Can you do it yourself? There is no definite answer, and here's why. If you are a technically competent person with experience in dealing with such equipment, and the motor is under warranty, it is advisable to obtain permission for scheduled maintenance from your nearest dealer. Most likely, such permission will be given, and then - down with self-confidence. Begin by carefully reading the instruction manual. In the list of routine maintenance, items are possible that are intended only for your specific motor. Lubricants and equipment used for servicing must be original.

After the expiration of the warranty period, the frequency and quality of maintenance remain on your conscience, although you will most likely not be able to completely avoid communicating with the service workers.In the list of routine maintenance specified in the operating instructions, there are those that require high qualifications, special tools and technical documentation. As for the various adjustments, the instruction limits the degree of intervention. You should be especially careful with carburetor settings. Excessively high idle speeds can lead to damage to gearbox parts due to the more severe shock mode when shifting gears. Incorrect adjustment of the mixture quality will lead to a deterioration in the engine operating conditions, which can entail quite serious consequences. I strongly advise against synchronizing the carburetors of four-stroke engines - without a special tool and a certain skill, the result will be negative. And one more tip: do not neglect the preservation of the engine (the procedure is described in detail in the instructions) and proper transportation, especially of four-stroke.

Repair associated with the replacement of any engine components or requiring serious diagnostics directly depends on the degree of technical training of the motor owner and equipment. The range of engines currently used on boats is diverse: they are simple carburetor engines, fuel injection systems for four-stroke and two-stroke engines, with OptiMax systems from Mercury and HPDI systems from Yamaha, and with various lubrication systems. All this requires constant professional retraining even from full-time mechanics. Of course, the owner of the motor is not faced with such a task, but he will not receive complete technical documentation for his motor anywhere. It is outlined in the "Service Manual" - a book used by mechanics. It does not go on sale. And if it will probably be possible to understand low-power carburetor motors, and flaws in the repair will not cause consequences, then a sane person himself will not approach a large motor, as "packed" as possible with electronics. And with all due respect to the craftsmen, I do not advise you to trust the engine to a master from a nearby garage. It is your motor that may be structurally different from those that it has successfully repaired before.

There is one more question, the answer to which must be found before proceeding with the repair: do you have a special tool? Having been engaged in the service of imported motors for far from the first year, I have seen enough and heard enough of everyone, but more often they say one thing: “Yes, I didn't have to do it myself. And how much will it cost now? " There is only one rule: if none of the tools you know are suitable for removing or unscrewing a part, stop - most likely a special tool is required for this procedure. I will say more, the tool that you think is suitable can affect the parts precisely in those places that cannot be loaded. In this case, you will not only break the part, but also significantly complicate the subsequent repair.

What I would like to draw the readers' attention to is the problem of spare parts. Where to get them, use "relatives" or find something suitable, does a worn part require replacement or will it still serve? In my practice, there was one motor on which an anti-corrosion anode, not original, but cheap, lasted longer than the engine, but at the same time had a very good presentation. Do not assume that all non-original spare parts are rubbish. There are also very worthy manufacturers. But, in my opinion, if there is an opportunity, it is better, instead of wasting energy, time, and therefore money on finding suitable ones, to contact technical specialists and be confident in the quality of the spare parts purchased. This, incidentally, also applies to oils. In addition, experts will advise which parts you need to purchase in a particular case, since quite often spare parts need to be changed in a bundle.

Replacing one part will not always correct the problem.A number of gaskets, lock washers, oil seals must be changed during repairs, even if they are outwardly in good condition. As for the clearances, permissible beats, torques and tightening sequence, then in this case it is better to get professional advice, at least by phone, e-mail or regular mail.

It is quite widely believed that it makes sense to purchase the simplest carburetor motors so that you can troubleshoot yourself. This is only partly true. Engines of small and medium power do not require complex technical solutions, but talking about the simplicity of high power motors, even if they are carburetor ones, is incorrect. In order to save gasoline and optimize the quality of the mixture, the fuel systems and ignition systems of such engines are quite complicated, which reduces their advantage over injection or the same OptiMax to a minimum. And given the best power and weight indicators of the latter and their efficiency, the question disappears by itself. Indeed, caution should be exercised when approaching fundamentally new and heavily compressed models. I will say more: complex motors, as a rule, have a protection system that notifies of faults that have occurred and changes the operating mode in such a way as not to damage the engine and at the same time operate it. A complicated-looking engine is often much easier to operate than a carburetor of the same power. Unfortunately, in this matter, many are still very conservative - the engine is frightening, the fear of the electronics with which the injection motors are equipped.

Considering all of the above, I highly recommend making repairs, adjustments and routine maintenance at a certified service center. It is certified. If, for financial reasons or due to the territorial remoteness of such a center, you are forced to carry out repairs yourself, then, again, it is still necessary to consult a specialist.

Within the framework of one or even several articles, it is impossible to outline all the subtleties of repairing an engine. But there are general trends in the maintenance of certain nodes. The table above lists the main points that must be taken into account when starting a repair.

D. Semenov, service manager, Mercury-NII TM, CJSC.

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Message hdx » 31.10.2011 01:13

Dear water motors, let us share the experience of repairing this motor in this thread.

I bought this HDX-15 motor in the spring of 2011, I ran it in completely satisfied, do not believe that the Chinese are bad.
But the trouble all the same happened on one of the solitary autumn days, it stopped developing momentum, that is, start everything up at idle, you accelerate, it seems like everything is in order, but in the load it does not gain momentum when you abruptly release the gas it stalls.
It was immediately clear that something was wrong with the fuel system.
I thought the carb was clogged
there is a filter in front of it, at first it looked everything is ok there the mesh is clean, I think out of my mind I will clean the carb all the same, but then a breakdown crawled out, it turned out that the carburetor pins were loosened and for this it sucked air (it seemed like a poor mixture was obtained), pulled it up and again everything was ok.
But here's the catch, I unscrewed the carburetor, somebody knows how to properly regulate it, for this motor it works normally, idle keeps it, but the consumption seems to be more.

Comrades, let's both of them without flooding. The man figured it out himself wrote what helped. Others will have a hint. there is no need for unnecessary disputes and an increase in messages in the topic, otherwise you will get tired of reading until you get to the bottom of the problem.

Thank you for your understanding, I hope I didn't offend anyone

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Thank you for the most interesting posts on the forum.

How to get here? To get on the Hall of Fame, you need to write posts and comments on the forum, and receive thanks from other users for them. Once a week, all thanks are summed up, and the user who has been thanked the most times over the past week gets to the honor board.

We constantly hear China bullshit and like add another half of the Chinese and buy a proven one over the years.
The Chinese have been in our country for several years and there are already statistics of their operation, let's share what, how and under what conditions did you break down?
I know that there are specialized topics for each brand, but I want to collect more reviews about the Chinese from the owners here! (and not from those who saw and heard something somewhere)
In fact, I would like answers of the form: The exact name of the motor, operating time, breakdown, cause, elimination time (search for spare parts, etc.)

———- Post added at 14:04 ———- Previous post posted at 13:58 ———-

I'll start with myself.
my first experimental subject after my grandfather's neptune was
SEA-PRO T 9.8 of the first untested batches of commercials some 5-6 years ago, at 7 hours of running-in, like many others, the petal valves crumbled and the motor stood for a month and a half in the warranty (there was no zch) summer without a motor was ruined, after repair it was still summer for me pleased with reliability.
the second was HIDEA 9.9 FHS, blown away at 15, here the troubleshooter had a complete canister, the thread on the plug came off for 1 week, but thanks to the representative of hidea, a new canister was sent to me and the engine made me happy for 3 years. until I myself ran into the rocks and bent the propeller shaft and the propeller for ejection (repair 7 thousand, I think it's not expensive)

Homemade cars, tractors, ATVs and ATVs

Do-it-yourself bulkhead and repair of the Veterok-8 boat motor: a photo of the work done, as well as a video of the boat motor after repair.

Hello everyone! Here I went over my outboard motor "Veterok". This business is very interesting for me. Of course, it was possible to take a used Japanese or Chinese motor, I just got into the taste of repairing a "sovkomotor", which is still needed for a "mental" rest.

The following work has been done: complete disassembly of the Veterok motor for components, revision of the gearbox, replacement of the pump, replacement of the pump bearing and oil seal, pump mirrors, replacement of all gaskets where possible, complete repainting, replacement of all rubber (tubes) on the motorcycle head.

The first start-up showed good performance of the motor, the "hot" starts from "half turn", the cooling works perfectly.

In general, I am glad of the work done, then photos and videos with a motor.

Replaced the bearing, oil seal and pump cup gasket.

In the photo: the already assembled gearbox and pump.

Updated the swivel clamp.

Slewing gear, clamp and control plate.

As a result, an old Soviet-made outboard motor is back on track.

This video shows the operation of the Veterok-8 outboard motor after the bulkhead.

Video: operation of the outboard motor at low gas.

Video: trolling on Veterka-8.

Having prepared a container that allows you to see the oil in the light, it is necessary to drain the oil from the gearbox and examine its color and consistency. Fresh oil should have a coffee color, settled oil should be transparent yellow. A creamy shade indicates the ingress of water - in this case, it is necessary to revise the oil seals. Large (not powdery) grains of metal in the oil indicate damage and the need to completely disassemble the gearbox;

The mounted shaft must be tested with a runout indicator. Values greater than 0.22 mm. talk about deformation. During normal operation of the gearbox, there should be no play at the end of the shaft;

To remove the oil seals, it is necessary to remove the gear cover from the screw side using flat screwdrivers or a puller. There is a rubber O-ring under the cover, it is recommended to replace it. After removing the bearing, you can replace the propeller shaft seal - its wear is the most common cause of impurities in the oil. It is also recommended to revise the gears of the gearbox, clean them from dirt and lubricate them.

The assembly of the gearbox is carried out in the same way in the reverse order. To increase the overhaul period, experts recommend paying special attention to the choice of high-quality oil for lubricating all engine elements.

Don't have time to repair your outboard motor with your own hands? The specialists of the "Marine Knot" company will professionally carry out a full technical check of your engine and eliminate all problems. Checking the outboard motor in our workshop can be done in no time. If you do not want to miss the good weather for fishing and recreation, we will also be glad to offer you motors from our catalog, which can be rented in just 10 minutes.

dqdmitry »28 May 2014, 18:22

I propose in this thread to share my experience in troubleshooting on the PLM "on the knee", on the water, right at the exit.
Typical breakdowns, their search, and repair. Who and how got out of different situations. Starting from banal operating errors, ending with more serious malfunctions.
What tool, what spare parts and accessories you need to carry with you, and how to use it.

To begin with, I'll try to put together what I found from different sources.

So. Simple situation - the engine won't start. Where to start troubleshooting?

If the engine refuses to start, then first of all it is worth checking all the electrics for serviceability, and then the fuel system.
You can start by unscrewing the spark plug. If everything is normal with the fuel system, then there will be fuel residues on the spark plug electrodes.
The presence of a spark can be checked as follows: attach a candle with a thread to the cylinder block and turn the starter. The circuit will be closed and there should be a spark (with a working electrician).
You do not need to hold the spark plug by the insulator, you need to clamp it between the cylinder block and some other part.
You always need to have a set of spare candles with you, the candles must match the model to the motor, only then the sparking will be correct.
The selection of candles and their marking will be discussed later.

If there is a spark, but it is completely pale, then either the ignition coil or the magdino is to blame.
The ignition coil is visible, but the magdino coil must be looked for under the flywheel. It, generating current, charges the capacitor and discharges at the required moment through the thyristor, giving a charge to the ignition coil.
The operation of the thyristor is controlled by a Hall sensor, which is a switch and is located there in the area of the flywheel. Its operation settings depend on the ignition timing.

A malfunction in the ignition coil may be associated with burnt windings or terminal contacts.
If the motor is not particularly looked after and monitored, then the contacts inside the plug cap may oxidize.
It is recommended to drop a drop of a special anti-corrosion marine grease into the cap before or after the season.
But before the coil, it is imperative to check all the wiring, inspect all the contacts, perhaps this is a malfunction.
Thyristors rarely fail, especially with short and medium lifetimes.

The magdino coil is checked with a multimeter. Its voltage and resistance are measured. To check, disconnect its contacts from the motor circuit and attach the multimeter contacts to them.
The polarity in this case is not important, the coil produces an alternating current. The indicators for all motors are different, you need to look at the documentation for each motor.
For example. On the Mercury ME 5 M, the voltage should be 25 V. The same will be the case for the Tohatsu M 5 S and the Nissan Marine 5. If the magdino outputs 17 V, then the coil is faulty.

On a good level, it is recommended to check all motor electrics with an ohmmeter.
When purchasing a motor or soon after, it is advisable to find out the resistance that this motor model should have.
That is, check these values on a known good motor in order to be able to compare them in the future when determining a malfunction in an electrician.

When checking the ignition coil, measure the resistance of its winding. You just need to make sure that there is no resistor in the candle cap, if there is, then just remove the cap.
The resistance value can be obtained from your dealer or specialist service. If the resistance deviates from the standard values, the coil will have to be changed entirely, it is not collapsible.

It is also recommended to check the emergency stop button of the motor. There were times when the contacts in it remained closed even when the key was inserted.
To check, you can simply unscrew the button wire, which is bolted to the ground with a bolt. Then check the spark again.

The last thing to look out for is the electrical unit. A little black box with wires. But it breaks down very rarely. If everything except her is exactly correct and checked several times, then maybe the problem is in her.

Having checked all of the above, the problem may already be localized, the consequence of which is either poor ignition or its complete absence.
If everything is fine with the ignition, and the engine stubbornly refuses to start, then you can proceed to checking the fuel system.
Firstly, it is banal (and with this it was probably worth starting

check if there is fuel in the tank). Is the level high enough for the fuel pump to pump?
Secondly, it is also a common banality - they forgot to open the air valve on the gas tank. At the same time, a characteristic feature is that the plastic tank is compressed inward.

Next, you can already proceed to checking the carburetor. If it contains fuel and the candles are dry, then the carburetor will need to be examined and cleaned.
In addition to cleaning the nozzles from blockages, you can adjust the carburetor, it is described in detail here. There is nothing complicated about it.
A poor start of the engine can still be affected by a knocked-out ignition timing, and on 4-stroke engines, the timing mechanism.
With the timing, it is recommended to contact a specialized service, but the lead angle can be adjusted independently. Usually you just need to slightly increase or decrease it. "Spin" the motor without transmission, and where the flywheel is, you will see a frame with a sensor and screws for adjustment.
But you need to deal with ignition adjustments at least understanding the theory or having experience in this. With an incorrectly set angle, you can increase fuel consumption and even shorten the life of the engine. When ignited sufficiently late, the engine will generally not start at all.
As a last measure, you can still check the compression in the cylinders, but this is probably not for "field" conditions.

A little about spark plugs

Candle marking
Electronics, electrics and the engine itself are designed to work with the spark plugs specified in the documentation by the motor manufacturer.
Uninterrupted and long-term operation of the engine directly depends on the proper characteristics of the spark plugs.

Candle gap
The correct clearance has a direct effect on sparking and ignition. The gap sometimes changes over time and this affects the operation of the motor. A special dipstick is needed to check the gap. It is necessary periodically, as the electrode burns out, to set the gap according to the marking of the candle.

Heat number
One of the most important parameters for spark plugs.
The heat number is the heat transfer rate of the candle. A larger glow number indicates less heat absorption, the candle is colder, so to speak, and vice versa.
Hot plugs (with a low glow rate) are placed on unpowered motors. During operation, such a candle is self-cleaning even at low temperatures. Cold candles in such a motor will quickly fail, tk. the temperature for self-cleaning will not be enough. Too hot a spark plug will lead to glow ignition, which has nothing to do with normal sparking. So experimenting with the incandescent number is not worth it if you do not know exactly what it will lead to. But if you are a seasoned powerboat and have owned multiple motors, changing the heat number can improve the performance of your engine. For example, for trolling, you can put hotter candles with a low glow number. The plugs will self-clean at low rpm and periodic re-gas is no longer required. But do not change this number too much, maximum by 1 unit.

Visual identification of spark plug condition

After purchasing a motor, many fishermen begin to think about increasing its power. But can this be done?

Yes, especially if the engine is foreign made. The fact is that foreign companies often produce engines with a power reserve, but with installed limiters.

This is a common marketing ploy.to sell the same motor under the guise of different modifications. Such products have the same engine displacement, dimensions, gear ratio and weight, but only the indicated power differs.

Japanese and European companies put restrictions on their products to comply with environmental regulations. In many states, the use of powerful motors is prohibited by law, as this leads to an increase in harmful emissions.

That is why it is worth purchasing a less expensive low-power motor, because then the limiters can be removed, and you can get a strong motor, while seriously saving money.

Of course, this is not the only way to increase the power of outboard motors. This can be done by forcing the motor, changing valve clearances, etc. In theory, any motor can be "overclocked", but this is not always easy in practice.

If the boat can go into planing mode, then its engine is quite powerful.The glisser is good not only for its speed, but also for its economy due to the minimization of the contact area of the boat bottom with the water surface.

To find out how much power the motor will need for this mode, you need to use the following rule: every 20 kg of the vessel and the cargo in it requires 1 hp.

In other words, a boat with a total weight of 300 kg will require a 15 hp motor. This rule can also be used for reverse calculations: if your motor has a power of 7 hp, the boat must weigh no more than 140 kg to enter the glider. But in reality, the weight should be even lower.

The increase in power will avoid savings in payload and equipment. But how to increase the power of the outboard motor? The choice of a particular method depends on its type.

Raising the power of a two-stroke engine to the limit will require several precise steps. Please note that this will increase fuel costs as well.

Inspect motor for presence of throttle restrictor. To do this, squeeze out the gas and look through the carburetor air intake window. When the damper is fully opened to 90 °, it can be concluded that there is no limiter, otherwise it must be found and dismantled.
Look for a petal valve - it is usually placed between the engine and carburetor, however, in low power models, it can be located in the cylinder block. When you find him, see if his petal is pinned down by a steel plate, and if it is there, bend it back. As a result, the volume of fuel going into the combustion chamber will increase, which means that the power of the engine will also increase.
Disassemble the carburetor, drill out the diffuser, and, if necessary, the jet, but only by 0.1 millimeter. Please note that after completing the work, you will need to adjust the float level again. You can also buy a carburetor from a more powerful model of the same range, this will do without drilling.

If successful, if there is a significant increase in power, adjust the ignition angle, putting it in a slight lead. You will also need to change the candles.

In general, this type of motor hardly differs from the one discussed earlier, and similar methods must be used to accelerate it.

At the end of the work, the valve clearances must be re-adjusted - they must be slightly widened, since the fuel output will increase. It is also worth increasing the lead angle.
Some high-end models with high power do not have visible physical stops and plugs, since an integrated chip is responsible for adjusting the characteristics of the motor. In such a situation, there is little that you can do with your own hands; you will have to involve service specialists. They will be able to do chip tuning. But you can try to find special software on the network for self-reinstallation.

Before interfering with the operation of the motor, it is worth trying to change other parameters of the boat that can affect its speed:

Examine the screw carefully. The slightest chips and cracks will slow down the speed, so replacement or grinding of the screw is required. It is also worth trying to replace it with a "high-speed" model or a 4-blade propeller. The metal propeller will increase the efficiency of the motor by reducing the thickness of the blades.

Raise the motor higher to reduce the sternwood drag.

Distribute the load in the boat optimally.

Leave everything unnecessary on the shore before going out on the water. This includes the transom wheels and the second anchor, which can be changed to floating. Another way out is to reduce the volume of the gas tank.

Watch the pressure in the cylinders, it should always be at the maximum level.

Remember that high increases in engine power will reduce boat control. This is why it is worth tying yourself up, otherwise you risk falling into the water at a sharp turn.Unlike ancient times, when it was possible to hope for a tailwind to appear only by relying on the forces of nature, today you can move on the surface of the water in any direction without significant physical effort and in complete calm.Thanks to the scientists who obtained electricity for mankind and tamed the fire of an internal combustion engine, any boatman can independently attach some kind of motor to his floating craft.A boat motor can be made from many mechanisms that collect dust in a barn or garage and are not used for their intended purpose. Image - DIY Chinese boat motor repair

It often happens that equipment breaks down, and in order to repair it, you need to spend more than half of the cost of a new device. In this case, it is much easier to purchase a new device, and put the old one aside and use it as a source of spare parts and various bolts and nuts. It is from such devices that a boat motor can be made.

If such devices are not available, then such a mechanism can be inexpensively purchased on the secondary market. The main thing is that the engine is in good working order in such devices.

By minimally changing the trimmer design, you can arrange an excellent traction unit for a boat of any design. The engine and transmission in such a device already exist, it is enough to make a mount for the boat, and instead of a bobbin with a fishing line or a disc, install a propeller.

Before making a boat motor from a trimmer, it should be understood that the power of such devices is very low, and it is unlikely that it will be possible to move against a strong current.

The disadvantages of using this device include a high noise level. In addition, at a low speed of movement, you will have to breathe absolutely all the products of the "vital activity" of this system.

Electric outboard motors have excellent performance in terms of noise production and environmental friendliness. You can make a motor for a boat from a screwdriver, but the power of the device should not be less than 300 watts. A flexible shaft from the trimmer can be used to transfer torque to the propeller that is located underwater.

A small aluminum propeller from a car fan is used as a propeller, and car batteries with a capacity of 60 A / h are used to ensure a long operating time of such a device.

The disadvantage of such designs is the need to carry a fully charged car battery with you. The mass of such a part is more than 20 kg.... The disadvantages include the limited stroke of such a motor; after the battery is discharged, it will be necessary to manually set the boat in motion again.

The most powerful of the homemade boat motors is considered to be a device made from a walk-behind tractor. The equipment for the processing of the personal plot is equipped with robust and durable four-stroke internal combustion engines, which, when installed on the watercraft,

will allow him to develop a decent speed both downstream and against it. These engines are heavy and usually not used on PVC boats.

The easiest way to install a boat motor of this design is to make minimal alterations to the main structure. It is enough to attach a walk-behind tractor to the hull of the boat, and install aluminum blades instead of cutters. The blades must be located in the same plane with the shaft, which in this case is located perpendicular to the movement of the floating craft. The blades are in the form of rectangular plates, which with the lower half must be lowered into the water, and the upper part must move freely through the air. Such a paddle wheel arrangement will allow you to move at high speed even in places where the depth does not exceed half a meter. A boat engine made of a motor-block with a fast current does an excellent job.

You can make a homemade engine not only using trimmers and screwdrivers as a basis.If there is a desire to design a boat motor independently and there is a significant margin of time and money, then any technical device equipped with an internal combustion engine or driven by an electric motor can be used as a power unit.

Many craftsmen put motorcycle engines on the boat. In this case, it is possible to adjust the propeller speed by shifting the gearbox. Powerful 12-volt motors, which are used in various mechanisms, can be successfully used as boat engines.

Making a boat motor is not difficult at all - it is enough to prepare all the parts necessary for this and assemble the device in such a way as to exclude the possibility of damage to the boat during the operation of such a unit, and to ensure safety for people.

The easiest way to make a homemade motor from a trimmer. For assembly, you will need the following materials and tools:

Trimmer.
Spanners.
Pliers.
Screwdriver.
Grinder or hacksaw for metal.
Drill and twist drills for metal.
Hairpin 12 mm.
Vise.

To manufacture a working version of the outboard motor, you will need to purchase a trimmer. Any model can be used, but the more powerful the device, the higher the speed characteristics of the boat.

Making a propeller is the first place to start. A duralumin plate with a size of 100 - 30 mm is used for the screw. Exactly in the middle of such a plate, a hole must be made to install it on the trimmer shaft. The hole diameter depends on the thickness of the gearbox shaft and is usually 17 mm. Before bending the duralumin plate, it must be annealed. Then, with pliers, each side is slightly bent so that, with axial rotation of such a plate, its step is no more than 10 mm.

Then the reel is removed from the mower and a screw is installed in its place. It is necessary to tighten the nut well so that the screw does not turn during operation. The trimmer discs are fixed with a left-hand threaded nut, so when the outboard motor is running, there is no need to fear the loss of the propeller due to unscrewing the nut.

Then you need to make reliable fasteners with which the trimmer will be installed on the boat. On the trimmer body, at the junction of the two halves, there is a ring for attaching a belt. It is this part that will connect the trimmer body to the boat. It is necessary to make a mount that will reliably connect the hull of the boat with the "eye" of the trimmer. For this purpose, you can use a mechanical meat grinder, in which the lower part is separated with the help of a grinder or a hacksaw for metal. Then a hole with a diameter of 12 mm is made in the body of the resulting clamp. The hole must be in the transverse plane of the screw clamp.

A piece with a length of 100 mm must be cut from a metal rod with a diameter of 12 mm. On one side, this section of the hairpin is slightly flattened and a hole with a diameter of 6 mm is made in it. A 6 mm bolt is threaded into this hole, on which the trimmer "eye" is installed. The bolt must be tightened with a self-locking nut.

The process of installing the motor on the boat takes place in the following sequence:

the mount is installed on the transom and securely fixed with a threaded connection;
a homemade boat motor is installed in the mounting hole.

The motor can be started and steered by keeping the hull of the outboard motor straight and, if necessary, tilted in the opposite direction of the boat's turn.

The use of a gearbox for a boat motor allows you to change the direction of axial rotation. The gearbox changes the speed of rotation of the shaft several times, which has a positive effect on the working resource of the engine. When equipped with a gearbox for a boat motor, you should adhere to the golden mean and do not install a device with a large gear ratio.Failure to do so will result in excessive fuel consumption, low boat speed and engine overheating. The safest way to install a gearbox with the optimum gear ratio for a given motor is to test several different devices. If during operation there is no excessive load, which manifests itself in the impossibility of a rapid set of high revolutions and the speed of the floating craft is quite high, then this gear ratio can be considered optimal for this engine.

Electric motors can be used as traction for boats without a gearbox. The pulling force of such devices is sufficient to work stably in the mode of direct transmission of torque to the propeller. An excellent engineering solution is the use of an electric motor underwater. With this arrangement, the screw is attached directly to the motor shaft.

It is not easy to make a motor with a gearbox on your own, but such a design will allow you to change the speed of the boat and change the traction characteristics of the propeller. This design is convenient when fishing by trolling, in addition, shifting to a lower gear will allow the boat to move more efficiently against strong winds and under significant load.

The most compact version of the engine, which can be made independently, is a device in which a two-stroke engine from a Karpaty moped is used as a power unit. Such a device will have only two speeds, but this is quite enough.

The engine is mounted on a self-made frame, which is a cut off part of the moped frame. The right cover and the drive sprocket are removed, and a small gearbox is attached to the shaft, to which a standard "leg" from the "Whirlwind" outboard motor is then attached, along which the torque is transmitted. All parts must be installed in such a way that the structure is as balanced as possible, otherwise a noticeable skew will be felt during movement, and when using such an engine with a PVC boat, the floating craft may overturn. The control handle for such a device must be at least 0.5 in length, otherwise, while driving the boat, you can get burns from the hot engine and the knee of the muffler.

The advantages of such a boat motor are very quiet operation, low fuel consumption and the ability to downshift when necessary.

Video (click to play).