Properly mounting the motor on a transom is fundamental not only to the comfort of the swimmer's operation, but also to your personal safety. Mistakes made during the installation phase can lead to engine overheating, cavitation, premature propeller failure, and even to the tipping of the boat at a sharp set of speed.
Unlike the temporary fixation, the professional installation It requires precise geometry, squirrel board materials and the right choice of fasteners. In this article, we will discuss all the nuances that will help you avoid common mistakes and ensure stable operation of the power plant on water.
Features of the transmutation design and types of fastenings
Before proceeding to the physical mounting of the power unit, you need to conduct a thorough analysis of the design of the stern part of the boat. Tranza It is a vertical or inclined plane that perceives the main traction load, so its integrity and rigidity are not in doubt. Modern PVC boats are often equipped with inflatable tubes with a glued or removable transom, while metal and plastic boats have a rigid design that requires a personal approach to the construction of the vessel. fixation.
There are two main types of attachment: strubzin (hinged) and bolt (stationary) mounts, which come with the motor, allow you to quickly remove and install the engine, which is convenient for transportation. However, when operating at high speeds or in conditions of high vibration, the rods can weaken, requiring periodic removable energy. suspender.
Fixed mounting through drilled holes in the transom is considered more reliable for powerful motors, it eliminates the risk of the motor slipping from the transmuter board when hitting a wave or at full speed. broad-bond and reinforced washers to distribute pressure on the contact area and not to push the transom material.
When using rods, always check the nut tightening before each release to the water - vibration can weaken even tight connections in 15 minutes of operation.
Rules of centering and horizontal alignment
The critical step is to ensure that the motor is strictly horizontally positioned relative to the keel line. If lower unit is skewed to the side, the boat will be led aside when moving, which will require constant steering and lead to uneven wear and tear. propellerIn addition, the skewed motor creates water resistance, which negatively affects efficiency and maximum speed.
To align, use the building layer by mounting it on an anti-cavitation plate or on a lower unit bracket, adjusting by placing gaskets under one of the plumbing or by shifting the motor across the transom if the design allows. marking holes.
Remember, the alignment needs to be checked not only in statics, but also in dynamics, at medium revs. Sometimes under load, the structure can shrink or shift, especially if used. timber-treeRegular visual monitoring of the position of the motor will help to avoid problems in long-distance navigation.
☑️ Checking the centre
⚠️ Warning: Never ignore engine skewing of more than 2-3 degrees. This leads to air capture by one side of the screw, which causes sharp jerks and can damage the gearbox.
Determination of the optimal height of the lower unit suspension
The height of the engine is perhaps the most delicate part of the entire installation procedure, which determines whether the engine will run at optimal speed or constantly overheat. The main reference point is an anti-cavitation stove. Ideally, it should be located 15 to 25 mm below the bottom of the boat so that the flow of water washes it evenly, but it does not create excessive resistance.
If you set the engine too high, water-intake It's going to get above the water level, which will cause air to enter the cooling system and cause instantaneous overheating, which is fatal to the pump and the engine body, and if you lower the engine too low, water resistance will increase, speed will drop, and the lower unit and screw will start to grow algae faster.
For flat-bottomed boats, you can put the engine a little higher, because they're on the surface of the water. V-bottom The lower unit is lowered down so that the screw works in a clean stream without capturing the air bubbles formed at the transom. Accurate adjustment is done by trial swims, followed by adjusting the height of the rods or drilling holes.
Signs of improper height of the suspension
If you see that the stream of water from the control hole has become intermittent or is coming with air, the engine is too high. If the boat is "sniffing" and does not go well for planing, and fuel consumption has increased, most likely, lower unit is buried excessively.
The angle of the differentiator and its effect on driving performance
Adjusting the angle of inclination of the lower unit allows you to control the behavior of the boat on the water. By changing the slope, you redistribute the thrust vector, which affects the position of the nose of the boat relative to the water. turret.
If the boat's nose is too upside down, it will go off the wave, hit the water with the bottom plane and lose its course stability, in which case you need to reduce the angle of the differentiation by tilting the engine closer to the transom, and if the nose is buried in the water and the boat sluggishly reacts to the gas, you need to increase the angle of inclination, taking lower unit further from the stern.
On many modern motors, adjustment is carried out with the help of hydrocompensator Or a mechanical stop with pins. Experiment with calm water settings, fixing the position of the pin for each loading mode of the boat, remember that the ideal angle for two people on board may not be suitable for solo swimming.
| A symptom. | Probable cause (Angle) | Action. | Impact on speed |
|---|---|---|---|
| The nose is slammed, the boat is "jumping." | Too much different | Tilt the motor to the transponder | Decline due to sailing |
| Nose buried in water, bad acceleration | Too small a different | Deflect the motor from the transom | Decline due to resistance |
| Boat's going straight, nose's a little raised | Optimal angle | Leave it unchanged. | Maximum efficiency |
| Rotor cavitation at corners | Incorrect angle or height | Integrated regulation | Dramatic loss of traction |
The ideal angle of the differentiation is a compromise between the maximum lifting of the nose for glides and sufficient entrapment of the screw for the absence of cavitation.
Safety technique during installation and launch
The process of installing the engine involves risks associated with both weight of equipment and mechanical damage. Motors weighing more than 20 kg are strongly recommended to be installed alone, especially on a slippery or rickety transom. Use a safety cable, worn through the engine's rim bolt and fixed to the strong element of the boat, to prevent the engine from falling into the water when the hands slip.
Before you first run, make sure you check the reliability of all threaded joints. Vibration is the main enemy of the fastener. counternuts or fixing compounds (e.g. Loctite) on threaded rods, if the design permits, also make sure that the fuel system is sealed and the hoses are not clamped by the mounting elements.
When working with gasoline engines, be aware of the fire hazard of fuel vapors. Do not smoke near an open tank and check the connections for leaks. Electric motors are critical to check the integrity of the wire insulation and the reliability of the battery terminal contact to avoid short circuits and oxidation of contacts with salt or fresh water.
⚠️ Warning: Always remove the engine from the safety stopper (if any) before starting and make sure the safety check switch is in the operating position. Starting without a check can lead to uncontrolled movement of the boat.
Maintenance of fasteners and preparation for the season
After the engine is installed and the first hours of operation, the fasteners must be re-diagnosed. Under the stresses, new parts can shrink, which requires re-tightening. graphite-lubricant or silicone to prevent metal from boiling and to ensure smooth adjustment of height.
If you use a boat in salt water, wash the fasteners with fresh water after each foray. aluminum And steel, which causes rapid corrosion, which can weaken the transom mounting design in one season, and look at the metal's contact with the transom for cracks or scuffs.
When stored in the off-season, it is better to remove the engine, especially if the boat is stored in an unheated room, which will prolong the life of rubber sealers and protect the paint coating of the lower unit. If removal is not possible, relax the puff of the rods to relieve stress from the metal of the transom, and cover the engine with a protective cover.
Seasonal storage
Before long-term storage, treat the metal parts of the mounts with conservation lubricant. Do not leave the motor hanging on the rods under its own weight for months - this can lead to deformation of the tanning board.
How often should I check the puff of rods?
It is recommended to perform a check before each outlet on the water visually, and a physical check with a key - after the first 15-20 minutes of operation of the engine and then every 2-3 hours of operation.
Can the engine be more powerful than the boat manufacturer recommends?
Exceeding the maximum power of the engine can lead to the destruction of the transom, loss of stability of the boat and imbalance, which is dangerous to the life of the crew.
What to do if the screw touches the bottom in shallow water?
You need to immediately raise the engine (if the design allows you to go) or to stop the engine. Constant impacts of the screw on the bottom lead to failure of the datawit and gearbox, in such cases, you need to revise the height of the suspension or use a screw with a smaller pitch / diameter.
Do I need to use a thread locker when installing the motor?
Using a medium-fix thread fixator (blue) on the bolts of mounting rods and brackets is a good practice to prevent spontaneous unwinding due to vibration. However, do not use a strong locker (red) if you plan to remove the motor often.
How do you know if the boat’s snare is weak and needs to be reinforced?
The signs are: cracks in the mounting site of the rods, excessive flexibility of the transom under pressure, displacement of the motor under load even when tight tightening, in such cases, you need to install a transom plate or replace the transmolator board.