Self-assembly of an outboard motor is often the only reasonable option for small craft owners who want to save money or get unique specifications not available in production models. lifan The 9 horsepower engine is attracting attention for its availability, maintainability and market prevalence, but standard powertrains of this brand tend to be equipped with a horizontal power take-off shaft, which requires specific engineering solutions to pair with a lower unit.
Use of the right verticalshaft (or adapting to it) opens up the possibility of compact and efficient propeller groups, where torque is transmitted directly or via a simplified transmission, which reduces friction loss in corner gearboxes, which is especially critical for low-power engines, where every horsepower counts. In this article, we will discuss the technical aspects of such an upgrade, focusing on nuances that are often overlooked by novice motorists.
The process of reworking or selecting the right modification requires a precise understanding of the mechanics of the work. four-stroke Errors in the design phase of mounting or gear ratio selection can lead not only to a decrease in the speed of the vessel, but also to fatal failures of the components. Therefore, before starting work, you need to carefully study the design of the chosen unit and possible ways of its integration into the body of the outboard motor.
Technical specifications and design features
The basic element of any homemade machine becomes a power unit, and in this case we are considering the models of the series. Lifan 190F These engines have proven to be reliable workhorses capable of operating under load, but the standard configuration assumes a horizontal shaft output, whereas the outboard motor of the classical circuit often requires vertical orientation or the use of a complex angle gearbox. 9 hp power. It is optimal for PVC inflatable boats up to 4 meters long and light aluminum boats.
The engine is a single-cylinder air-cooled unit, which imposes restrictions on operating modes, and unlike the two-stroke counterparts, there is a full-fledged crankcase lubrication system that requires oil level control. Vertical shaft in factory performance is rare, so most often we are talking about installing the engine on a special frame with the subsequent transfer of rotation through a belt or chain gear to lower unit, or the use of specialized gearboxes.
Particular attention should be paid to the centrifugal clutch system, if it is provided in the selected modification, or plan the installation of a separate clutch assembly / gearbox. The absence of neutrality on a pure Lifan engine requires additional solutions for controlling the boat. Below is a table comparing the basic parameters of the standard horizontal shaft and the required specifications for boat adaptation.
| Parameter | Standard Lifan 190F (Horizontal) | Requirements for outboard motor | Note |
|---|---|---|---|
| Orientation of the shaft | Horizontal | Vertical (through gearbox) | Angular gearbox required |
| Power | 9.0 - 9.5bhp. | 7.5 - 8.5 hp (on the screw) | Transmission loss accounting |
| Turnover max. | 3600 rpm | 5000-6000 rpm (for a screw) | Requires a booster gearbox |
| Lubrication system | spraying | Stable at roll to 15° | Risk of oil starvation |
⚠️ Attention: Installing a horizontal shaft engine without a proper gearbox will make it impossible to use a standard propeller. Direct connection of the shaft to the propeller without changing the plane of rotation is not technically feasible for a classic outboard motor scheme.
Problems of the vertical shaft and ways of adaptation
The main technical difficulty is that the massively available Lifan 9 hp engines have a horizontal shaft. verticalshaft In this context, it is often desirable, but it requires implementation through gear mechanisms. Direct installation of such a motor "upside down" is impossible because of the design of the lubrication system: oil flows from the crankcase, and the engine will jam after a few minutes of operation. So the term "vertical shaft" here rather means the creation of a vertical axis of rotation of Daydwood.
There are several proven ways to do this: the most common is to use an angle gearbox from a decommissioned outboard motor (for example, from a Wind or Salyut), or to buy a specialized Chinese spare part that connects to the engine shaft. The other option is a belt gear, where the pulley on the engine crankshaft is horizontally located, and the second pulley is fixed to the vertical shaft of a lower unit, which allows you to maintain the correct position of the engine and ensure the necessary transfer of torquement.
When choosing the way to adapt, it is critical to consider the direction of rotation. A standard gasoline engine rotates clockwise (as viewed from the shaft side); the outboard motor propeller must also rotate in a certain direction to create thrust. If you use a gearbox from a two-stroke motor, the direction of rotation can change or remain the same depending on the number of gears. Reverse gearbox In such assemblies, it is often absent, which limits maneuverability.
Why can't you just flip the engine?
In oil-spraying engines (through a crankshaft or scoop), an inverted position will cause oil to drain into the cylinder head or leak through the sapoon. In addition, the carburetor and air filter may not work properly in the inverted position, and the GRM valves may disrupt the thermal gaps due to changes in the gravitational effect on the barbells (in OHV motors).
It is also important to note the difference in rpm. The Lifan engine develops maximum power and torque in the range of 2500-3600 rpm. The small diameter propeller installed on the outboard motor requires significantly higher rpm (5000-6000 rpm) for efficient operation. Without upshift (for example, 1:1.5 or 1:2), the boat will not develop the design speed, and the engine will operate in overload mode.
Necessary tools and preparation for assembly
Building a homemade outboard motor is not just a bolt-wire-wire-wire, it's a complete engineering task that requires precision and appropriate tools. lifanYou need a welding machine to make the frame (if it is made from scratch), a powerful workbench and a set of locksmiths. The lack of a quality tool can cause the shafts to skew, causing vibration and rapid wear of bearings.
The key element of preparation is the design of the transition flange, and it's this part that connects the engine output shaft to the input of the gearbox or the diewood, and the precision of the fabrication is measured in tenths of a millimeter, the use of homemade centerings without a lathe is unacceptable, and the system for attaching the engine itself to the lower unit tube, which must withstand vibration loads and hydrodynamic shocks.
The list of necessary equipment and materials includes not only the engine itself, but also many related components. Don't skimp on fasteners: vibration has the ability to unwind even well-tightened bolts. Use engrovers, thread fixers or self-contradicting nuts. Pay special attention to the condition candle-wire and high-voltage coil, since in conditions of humidity and spray, the risk of insulation breakdown increases many times over.
☑️ Checklist for assembly preparation
Step-by-step instructions for installation and assembly
The assembly process begins with the construction or preparation of the ram, the engine must be rigidly fixed to prevent the rotation axes from shifting under load, the first step is to install the engine on the prepared site. carburettor The air filter is not covered by the elements of the structure, as these components require regular maintenance.
The next step is to dock with the transmission. If you use a belt gear, you need to ensure that the belt is properly stretched. Excessive tension will overload the crankshaft bearings, and weak tension will overload the crankshaft bearings and lose power. If you use a gear gear gearbox, you need to precisely align the shafts. The slightest skew will cause the characteristic hum and heat of the knot in the first minutes of operation. plug-inIt compensates for micro-vibrations.
After mechanical assembly, the engine life support system is connected. The fuel tank is installed above the level of the carburetor for gravity or equipped with a pump pump. The fuel line must be gas-resistant, without clamps. The ignition system is checked for a spark. The muffler is displayed sideways or upwards, but always with a sparker to eliminate the risk of fire, especially on boats with wooden elements or in dry grass near the water.
⚠️ Warning: It is strictly forbidden to start the engine without the installed cooling system of the lower unit (if it is water) or without immersion of the screw in water.
For the first break-in, assemble the engine, but do not install the propeller immediately. Start the engine for 5-10 minutes at idle speeds to check the tightness of the fuel system and the absence of vibrations that can destroy the welded seams of the frame.
Fuel system setup and start-up
Lifan engines, like most Chinese counterparts, often come with basic carburetor settings that are not optimal for working as part of an outboard motor. Under load, when moving against the wave, the mixture can be too poor or too rich. Adjustment is made by screws of quality and quantity of the mixture. Perfect setting ensures stable revs and no "failures" when abruptly opened. throttle.
Air filtration is an important aspect. In the water surface, air humidity is present, and water can enter the air filter with the spray. A standard paper filter is not suitable here, it will instantly soak and block air access. It is recommended to use oil baths or special zero resistance filters with water repellent impregnation. Regular inspection of the filter condition is the key to the long life of the engine.
The engine is started according to the standard algorithm: shut off the fuel crane (if any), open the air valve (suction), pull the starter. After warming up, the valve is closed. Particular attention should be paid to the length of the gas control cable. It should have a minimum backlash, but also not be stretched like a string, so as not to cause spontaneous addition of revolutions due to the vibration of the boat hull.
In operation, you may need to adjust the ignition advance angle if the design allows. However, on most Lifan 190F models, the ignition angle is fixed. If the engine detonates or overheats, it is worth checking the fuel octane number and the condition of the cooling system. Using fuel with an octane number below the AI-92 can lead to the destruction of the piston group.
The correct configuration of the carburetor is more important than maximum power: it is better to lose 5% of thrust, but ensure stable operation of the engine in all conditions, than risk a piston burnout due to a poor mixture.
Operation, maintenance and typical errors
A homemade outboard motor requires more attention than a factory-made one, and the main enemy of this design is corrosion and vibration. After each watering, the engine must be desalinated (if used in salt water) and dried. Vibration gradually weakens the threaded joints, so once a season it is recommended to stretch all the bolts, especially the engine attachment to the frame and the lower unit to the transom.
A common mistake is to ignore oil change: Air-cooled engines have a more severe temperature regime than water-cooled engines; oil loses its properties faster; it should be changed every 20-25 hours using synthetic or semi-synthetic oils with high temperature tolerances (for example, 10W-40). spark-plug: black colored coar will indicate a rich mixture, white - poor.
Another common problem is cavitation: if the lower unit pipe is set too high or the screw is picked up incorrectly (too big a step), the screw begins to capture air. This leads to a sharp increase in speed without increasing speed and overheating the engine. Optimal deepening of the anti-cavitation stove is 5-10 cm below the keel of the boat when fully loaded.
⚠️ Warning: Never leave fuel in the carburetor for long-term storage. Gasoline evaporates, leaving a resinous plaque that clogs the jellyplants. Be sure to run out of fuel before the engine stops or shut off the faucet before wintering.
Frequently Asked Questions (FAQ)
Can I use the Lifan 9 hp engine for planing on a 3.5-meter PVC boat?
Yes, it's a real possibility. A 9 hp engine can plane a 3.5-3.8-meter inflatable boat with one adult passenger and minimal load. However, success depends on the right propeller (diameter and pitch) and the total weight of the gear. For heavy boats or full loads, it's best to consider engines ranging from 10-12 hp.
What is the life of the Lifan engine in outboard mode?
With proper running, timely oil change (every 20-25 hours) and quality fuel, the engine life is 500-800 hours before major repairs. In outboard motor mode, where loads can be higher due to operating at the limit speed, the resource can be closer to the lower limit.
Do you need water cooling for this engine?
The Lifan 190F engines are air-cooled and water-free. However, lower unit (the bottom with the propeller) usually requires water-cooling to lubricate the propeller bearings. The engine itself is cooled by incoming air flow, so when installed on a boat, you need to ensure free air access to the cylinder and not cover it with blank casings without forced ventilation.
Where to find spare parts for the gearbox if the standard ones do not fit?
Often, craftsmen use gearboxes from Soviet engines "Veterok-4/8", "Salute" or Chinese analogues (Hidea, Parsun), adapting seats. There are ready-made Chinese gearboxes designed specifically for the shafts of engines such as Honda GX160/200 (similar to Lifan 168F/190F), They can be found on specialized sites or from suppliers of components for mini-engines.
Is it safe to use a homemade motor on water?
If all the connections are made reliably, the locking elements are used, there is an emergency check (the cable, the engine jamming when a person falls overboard) and fire safety rules are observed, then operation is permissible. However, remember that homemade equipment is not certified, and the responsibility for its safety lies entirely with the owner.