The shift to hydraulic control of the outboard motor is not just a replacement of the cable, it is a fundamental change in the comfort and safety of the boat. Many owners of boats and PVC boats face a situation where standard mechanical control becomes "tight" or not accurate enough as the engine power increases. hydraulics.
The hydraulic drive ensures smooth running of the hummel even at high speeds, completely eliminates the backlashes and "feedback" when the wave shocks are transmitted to the hands of the steering officer. Unlike mechanical systems, there are no rubbing metal cables that over time stretch and require constant lubrication. Installation of such a system opens new horizons in maneuvering, making the control of a boat with a powerful power. motor It is accessible even to a physically weak person.
In this article, we will discuss in detail how to choose the perfect set, what are the nuances of hydraulic cylinder installation and why maintaining this system requires strict compliance with regulations, you will learn about the differences between outboard and stationary engines, and also get practical recommendations for removing air from the circuit, which is a critical step.
Principle of operation and advantages of hydraulic control
The basis of any hydraulic steering system is Pascal's law, which says that the pressure exerted on the liquid in a closed vessel is transmitted without change to every point of the vessel. In the context of an outboard motor, this means that the force you apply to the steering wheel is transmitted through a special fluid (hydraulic oil) to the piston in a cylinder attached to the motor. This allows you to convert small movements of the steering wheel into powerful and accurate movement. lower unit.
The main advantage of this is that there is no direct mechanical connection between the steering wheel and the engine. You don't have to put physical effort into overcoming the water resistance of the steering pen or the motor itself. The system works as an amplifier: the larger the piston area in the cylinder relative to the piston in the steering wheel, the greater the output force, especially for motors over 115 hp, where mechanical control is no longer efficient.
⚠️ Attention: The hydraulic system does not tolerate air. The air that enters the circuit compresses, unlike the liquid, which leads to a "cotton" steering wheel and loss of control.
In addition, hydraulics allow the control post and engine to be carried over a considerable distance without loss of efficiency, which is impossible to implement with cable systems due to their stretching and friction. The coil becomes light, informative and predictable in any conditions, whether it is calm or storm surge.
Main components of the steering system
Any complete hydraulic system consists of several key components, each of which performs its function. Understanding the structure of these components is necessary for the correct selection and subsequent maintenance. steering-machine (pump) steering-cylinder and connect them hydraulic hose.
The steering machine, or pump, is installed directly at the helm, and inside it is a piston that, when the steering wheel rotates, creates pressure in the system. Modern models often have a built-in valve block that prevents fluid from flowing when the waves hit, maintaining a predetermined course. The cylinder, in turn, is attached to the trunk of the boat and through thrust connects to the motor bracket.
- 🔹 Steering machine (Pump): Converts the rotational movement of the steering wheel into the linear motion of the piston, creating pressure.
- 🔹 Hydraulic cylinder: Actuator, which directly turns the motor in the right direction.
- 🔹 High pressure hoses: Special reinforced tubes that withstand constant pressure and aggressive marine environment.
- 🔹 Liquid (ATF): The working body of the system, providing the transfer of force and lubrication of internal components.
It is important to note that different types of motors (two-stroke, four-stroke, thruster) may require different types of cylinders. Power Trim and Tilt Often used cylinders with increased stroke or special fastening.
When choosing hoses, always take a length with a margin of 10-15 cm. This will avoid tension during the shifting of the steering wheel and will simplify future repair or replacement of components.
System choice: single-cylinder or two-cylinder circuit
One of the first questions a customer faces is whether to choose between a single-cylinder system and a two-cylinder system, which is directly dependent on your engine power, the size of the vessel and the desired comfort level. cylinderIt provides sufficient effort for confident management.
However, if you own a speedboat with a motor of 200 hp and above, or if your boat has a large sailing capacity and is subject to wind demolition, the clear choice is a two-cylinder system. Two cylinders mounted symmetrically on the transom not only double the force, but also balance the load on the engine's ram-lamb, preventing it from being distorted and worn.
Two-cylinder systems are also preferred for boats with a wide transom or specific geometry, where one cylinder cannot provide the required angle of relay. In addition, having two cylinders increases fault tolerance: if one of the circuits is damaged (although this is rare), you have partial control over the boat.
| Characterization | Single-cylinder system | Two-cylinder system |
|---|---|---|
| Recommended capacity | up to 150-200 hp. | 200 hp and higher |
| Difficulty of installation | Low (baseline) | Medium (requires symmetry) |
| Cost of kit | Budgetary | High. |
| Effort at the tiller | Standard. | Minimum (one finger) |
For lightweight inflatable boats with medium-power engines, a single-cylinder hydraulics will be an excellent upgrade, whereas for heavy metal or fiberglass boats, a two-cylinder scheme is the standard of safety.
Preparation for installation: tools and equipment
Before starting work on hydraulics installation, you need to carefully prepare the workplace and tools. Quality installation requires cleanliness, because even microscopic dust entering the hydraulic circuit can cause the sealing rings and valves to fail. You will need a standard set of locksmith tools, including keys, screwdrivers and drills.
Pay special attention to the choice of placement of the steering machine at the helm, it should be located so that the hoses approach it without strong inflections, and the steering wheel itself had free running. Often this requires the completion of the tiller niche or the manufacture of an additional bracket from the inside of the wheel. stainless steel or aluminum.
☑️ Preparation for hydraulics installation
Don’t forget to buy a quality hydraulic fluid. Usually it is an ATF (Automatic Transmission Fluid) transmission oil, but the specific type is always specified in the manufacturer’s instructions (for example, Dexron III), you will also need clamps to fix the hoses, insulation tape and possibly additional washers to align the cylinders relative to the engine axis.
Step-by-step instructions for hydraulics installation
The installation process begins with the dismantling of the old mechanical controls. Carefully remove the humming device, unplug the cables and remove the old mounts from the transom. Carefully clean the transom surface of corrosion and old sealant. This is a critical step, as new holes must be drilled in a clean and even material.
The next step is to install the steering cylinder, hold it on the transom in the center, using the level. The axis of the cylinder should be parallel to the plane of the transom, and the rod should be located approximately in the middle of its turn when the motor is neutral, and the distortion of the cylinder will lead to uneven wear of the glands and rapid failure of the system.
⚠️ Attention: Never tighten the cylinder nuts "deadly" without using counter washers or a thread fixer. The vibration of the motor at high revs can weaken any connection, which will lead to backlashes and loss of control.
Once the cylinder is fixed, the pump is installed at the helm, and the hose is the most critical thing to do: it should not rub against sharp edges, be heated by the exhaust system, or have a bend radius less than the permissible one. Stretching the hoses from cylinder to pump, leaving the ends open (but closed from dust) until the moment of connection.
Hose nuances
If you are running hoses over the side of the boat, be sure to use a passage bushing with rubber seals. Do not pass hoses through compartments with fuel tanks or batteries to avoid the risk of fire when depressurization.
Refueling and air removal
After mechanical installation, you get hydraulic wiring, you connect the hoses to the pump and cylinder, and you follow the labeling (usually "L" and "R" or color coding) before you make sure that all the connections are clean. You now need to fill the system with liquid and remove air. This process is called pumping.
There are two main methods of pumping, manual and special device, the manual method is to slowly rotate the steering wheel from the far left to the far right and back, and the filler lid at the pump must be ajar so that air comes out and the liquid fills the voids, a process that can take from 30 minutes to an hour.
To get better pumping, you can use a transparent hose, lowered into a liquid tank, connected to a pumping plug (if it's designed to do so), and you can see the air bubbles coming out of the wheel, and once the bubbles are gone and the steering wheel is heavy and elastic, the system is considered pumped.
- 🔸 Pour the liquid into the pump expansion tank to the maximum level.
- 🔸 Rotate the wheel slowly, without jerks, from stop to stop.
- 🔸 Monitor the level of the liquid and constantly add it, not allowing drainage of the pump.
- 🔸 Check the system for no leaks at all points of the connection.
After pumping, be sure to check the system on land by connecting the motor (or simulating the load). The tiller should walk smoothly, without jerks or dips. If you feel "failures" or jerks, then there is air in the system, and the procedure should be repeated.
Well, pumping the system is 90 percent of the success, and poorly pumped hydraulics will work worse than a good mechanical cable, and can cause a water emergency.
Maintenance and typical faults
The hydraulic control system requires minimal but regular maintenance. The main enemy of hydraulics is water, which can enter the system through microcracks in the omentums or improper pumping. Water causes corrosion of internal components and emulsification of the oil, which dramatically reduces its lubricating properties.
Once a season or every 100 hours, it is recommended to visually inspect the hoses for cracks, scuffs and bloating. Also check the level of fluid in the pump tank. If the level drops, look for a leak. If the fluid becomes cloudy (became like coffee with milk), then water has entered the system, and a complete oil replacement is required and the cause of moisture is found.
A typical malfunction is also the "suffocation" of the system after winter storage or long downtime, in which case it is enough to repeat the pumping procedure. If the steering wheel became tight suddenly, check whether the cylinder jammed due to dirt or deformation of the rod.
Remember that hydraulic oil (ATF) loses its properties over time, and it is recommended to change the fluid in the system at least once every 3-5 years, even if there are no visible problems, this will prolong the life of the seals and keep the steering wheel running smoothly.
How often should the hydraulic fluid in the system be changed?
Manufacturers recommend changing the liquid every 3-5 years or when there are signs of contamination (occurrence, presence of water), however, with intensive use in salt water, it is better to reduce the interval to 2-3 years.
Can I use regular motor oil instead of ATF?
No, you can't. Hydraulic fluids (ATFs) have special additives that prevent foaming and provide the necessary viscosity at different temperatures. Motor oil can damage seals and not provide the necessary pressure.
What to do if the wheel becomes very tight?
First, check if the cylinder mounts on the transom are pulled over, then make sure there is no air in the system. If the problem persists, maybe the valve block is clogged or the pump piston is damaged, disassembly and defectiveness is required.
Is hydraulics compatible with motors from different manufacturers?
Yes, most systems are versatile. The main thing is to choose the right type of cylinder mount (for example, for Yamaha, Mercury, Tohatsu there can be different brackets) and the horsepower of your engine.
Do I need to disassemble the cylinder for lubrication?
Hydraulic cylinders are serviceless in terms of lubricating rubbing vapors — they work in an oil bath. They need not be disassembled without the need (to replace cuffs during repairs) and external hinges sometimes require lubrication if the design so requires.