Any day on the water using an outboard motor is accompanied by vibration. combustion-engineWithout an effective system to quench these fluctuations, the pleasure of the trip quickly turns into fatigue, and the structure of the vessel is subjected to devastating effects.
The key element responsible for absorbing shocks and vibrations is shock absorberThis small device is often underestimated as a secondary part, but it is the one that keeps the transom intact and keeps the flow smooth. Ignoring the state of the shock absorbers can lead to costly body repairs or even loss of the motor during a storm.
In this article, we will discuss in detail how the suspension system is arranged, what types of dampers are available and how to replace worn-out parts on your own. transom-holding will help you avoid common errors in operation and tuning of the swimming aid.
Why do you need a shock absorber in the suspension system of the motor
The main function of shock absorbing elements is not only comfort, but also safety. Vibration.The swelling that occurs when the engine is running at high speeds is transmitted to the transom, causing resonant fluctuations in the hull. If the boat is made of PVC, constant shaking can lead to stratification of the seams or damage to the inflatable floor. In aluminum boats, vibration contributes to metal fatigue and microcracks.
Besides, shock absorber It acts as a damper when it hits a wave, or when it hits a wave crest, or when it brakes abruptly, the inertial force tends to pull the motor out of the mounts, and high-quality rubber or polyurethane inserts dampen that momentum, preventing the rods or the transom plate from breaking. Wearing These elements often cause backlash, which only increases with time.
⚠️ Warning: Operating a boat with completely destroyed shock absorbers can cause the engine to tear off and fall into the water.
And it's also worth mentioning the protection of the engine itself, and the excessive vibration, which is not extinguished by the suspension, is transmitted to the internal components of the engine: the carburetor, the ignition system and the lower unit, which accelerates the production of life. bearing The correct rigidity of shock absorbers extends the life of both the vessel and the power plant.
Types of shock absorbing fasteners for outboard motors
The aqueous accessories market offers several solutions for vibration quenching. The choice of the specific type depends on the design of the boat and the way the engine is attached. rubber-stickThese are rods that are mounted between the motor rods and the transuccines, and they're easy to replace and affordable.
A more advanced solution is considered polyurethane shock absorbersUnlike conventional rubber, polyurethane is less susceptible to aging under the influence of ultraviolet and fuels (flammable lubricants), which retain their elasticity over a wide range of temperatures, which is especially true in harsh climates. Toughness Polyurethane is usually higher, which may be preferred for high-powered motors.
- 🛠️ Staff rubber bushings - come with the engine, require frequent replacement due to rapid aging.
- 🛡️ Polyurethane cushions - durable rubber analogue, withstands aggressive environment and loads.
- ⚙️ Spring-and-pendulum systems complex mechanisms for heavy motors, extinguishing vibration in all planes.
Special attention should be paid to the systems of spring-pieceThey are often used on squirrel wheels or special PVC outboard systems. The spring works on compression and stretching, effectively absorbing low-frequency vibrations that rigid rubber gaskets cannot remove. The combination of various materials allows you to achieve an optimal balance between fastening rigidity and comfort.
When buying shock absorbers, pay attention to the labeling of the material. EPDM rubber is better at resisting ozone and aging than conventional technical rubber.
Signs of wear and the need to replace dampers
Determine that shock absorber The first and most obvious symptom is the appearance of an extraneous knock or rattle in the transom area when the engine is running at idle speed, which indicates that the gap between the metal and the damper has increased, and the metal hits the metal.
Visual inspection also provides a lot of information: rubber cells lose their elasticity over time, become covered by a network of small cracks or start to crumble. gasket If it's deformed, flattened, or has oil traces that it shouldn't absorb, it's time to replace, and ignoring those signs leads to the breakdown of the seats.
Another sign is increased vibration on the tiller or steering-wheel. If the motor was soft before, and now the control handle is vibrating so hard to hold, the problem is the mounting system, and sometimes the vibration is transmitted to the entire hull of the boat, making it uncomfortable, and in such cases, the shock absorbers should be checked first.
How to check the backlash without removing the engine?
Try to swing the motor side-to-side with the engine off and the lower unit up. If you notice a free ride or hear a knock at the place where the rods are attached to the transom, the shock absorbers require replacement. You can also insert a thin screwdriver between the rod and the transom — if it comes in too easily and without rubber resistance, the element is worn out.
Instructions for installing shock absorbers yourself
Replacing worn-out elements is a procedure that is available to any boat owner, and first you have to dismantle the motor from the transom. screw-screw If you have a bolt mount through a transom plate, you'll need to unscrew the nuts, which is more convenient with an assistant or on a special stand.
After removing the engine, thoroughly clean the contact surfaces of dirt, residues of old rubber and oil. degreaserIf you're installing universal shock absorbers that require fitting, you might need to drill holes or cut the extra ones, and the main thing is to ensure that the load is evenly distributed.
☑️ Tools for replacing shock absorbers
When you build, don't tighten the fastener all the way up. First, make all the bolts or screws to get the pieces in place. Then evenly, cross-cross-cross-cross, tighten the joints. Excessive force can lead to extrusion. rubber from the seat, which will reduce the efficiency of cushioning, after installation, check the density of the motor to the transom.
⚠️ Warning: Do not use solidol or litol to lubricate rubber shock absorbers. Petroleum products break the structure of rubber. Use only silicone lubricant or talc.
Tuning of the transom plate and strengthening of fastenings
PVC boat owners often face the problem of a soft transom, which is not able to effectively extinguish the vibration of a powerful motor. cross-plate It's a rigid plywood or aluminum structure that distributes the load from the motor over a large area of the side, increasing the overall stiffness of the stern.
When tuning, it's important to pick up the right shock absorbers between the stove and the motor, and too soft elements will lead to "sticking" of the motor and loss of planing efficiency, and too rigid will transmit all the vibration to the boat. It also makes sense to put extra stiffness ribs on the transom plate itself.
For aluminum boats, it's important to install antivibration linings on rods. liner They're made of thick rubber or polyurethane, and they're put directly on the paws of the motor attachment, and this simple solution allows you to reduce noise and vibration significantly without the complicated rear-facing.
| Type of boat | Recommended material | Replacement frequency | Features |
|---|---|---|---|
| PVC (inflatable transom) | High-density polyurethane | 1 time in season 3-4 | High resistance to the sun and punctures |
| aluminum | Oil-resistant rubber (NBR) | 1 time in season 2 | Protection against HSM is required |
| Plastic (FRP) | Combined (rubber + metal) | 1 time in 5 seasons | It's important not to overpower the body. |
| Tree. | Soft technical rubber | Every year. | Protecting wood from rotting under metal |
Properly selected material shock absorber prolongs the life not only of the motor, but also the transom of the boat, preventing its destruction from constant vibration loads.
Questions and Answers (FAQ)
Can I use car shock absorbers for the outboard motor?
No, it is strongly discouraged. Automotive shock absorbers have a completely different operating principle (hydraulic or gas oil) and are not designed to work as support elements of the suspension in the horizontal plane or to quench high-frequency vibration of low amplitude. For boats, elastic elements (rubber, polyurethane) working for compression and shear.
How often should you change the rubber shock absorbers on the motor?
The life of the product depends on the intensity of operation and storage conditions. On average, rubber elements are recommended to be inspected every season before navigation begins. If there are cracks, scuffs or loss of elasticity, they must be replaced.
Why does the engine knock even after the shock absorbers are replaced?
There may be several reasons: the rigidity of new shock absorbers is not selected correctly, the fastening bolts are not tight enough, or the problem lies not in the suspension, but in the operation of the engine itself (for example, three cylinders), and the knock can emit a lower unit when hitting the water surface if the angle of inclination of the motor is chosen incorrectly.
Does the thickness of the shock absorber affect the speed of the boat?
Indirectly, yes. If the shock absorber is too soft or thick, the motor can go deeper or, conversely, to pick up the lower unit, which disrupts the hydrodynamics and reduces the efficiency of the screw. The correct height of the anti-cavitation plate relative to the bottom is critical for speed, and shock absorbers play a role in fixing this position.