The legendary Soviet Whirlwind 20 Despite its age, this two-stroke engine is still widely used by anglers and water tourism enthusiasts due to its maintainability and availability of spare parts. Understanding its technical features is the key to long and trouble-free operation.
Many owners face the need to fine-tune or search for original parts, so detailed analysis of specifications becomes not just a theoretical exercise, but a practical necessity. key-periods The engine will help you assess its potential or make a purchase decision.
General concept and history of the model
Engine. Whirlwind 20 It was developed in the mid-1960s and was a logical extension of the low-power engine line of Kazan Engine Plant, the main goal of the engineers was to create a reliable unit for lightweight planing motorcycles, able to compete with foreign counterparts of the time, the design is based on proven solutions, which ensures high survivability of the mechanism even when using fuels of the lowest quality.
Unlike modern four-stroke analogues, this engine requires the preparation of a fuel mixture, which imposes certain obligations on the owner. Two-stroke cycle This is a very high power density with a relatively low weight, which is critical for small craft, but it's also a very strong requirement to keep the oil and gasoline ratios in place.
⚠️ Attention: Using pure gasoline without adding a special two-stroke oil will result in instant jamming of the piston group and expensive overhauls.
Over decades of production, the design has undergone minimal changes, which allowed for the unification of the units, which means that parts from engines from different years of production are often interchangeable, making it easier to find components.
Technical specifications of the engine
At the heart of the unit is a two-cylinder reciprocating-loop engine, which has a displacement of 346 cubic centimeters, which, at a declared power of 20 horsepower, gives an excellent indicator of litre power for the equipment of that period. Torque is distributed evenly thanks to a crankshaft rotating in opposite directions for the cylinders.
The ignition system is powered by magdinos, making the motor fully autonomous from external sources of electricity. Contact ignition It requires periodic adjustment of the gap and replacement of interruptors, but is easy to diagnose. Modern electronic units are often installed by owners themselves to improve the stability of spark formation.
To improve the start in the cold season, it is recommended to replace standard candles with higher-quality imported analogues with a potassium number corresponding to the instructions.
Cooling is forced, water is taken from the water body through the water intake and circulated through the channels in the lower unit and cylinder block. The efficiency of the system depends on the state of the impeller pump, which is an expendable material.
| Parameter | Meaning | Unit of measurement |
|---|---|---|
| Power | 20 | hp |
| Workload | 346 | cm3 |
| Rotation frequency | 4500-5000 | min |
| Weight (with screw) | 39-41 | kilogram |
Fuel system and carburetor
The engine is powered through the K-33 carburetor or its modification, which ensures the preparation of a combustible mixture. carburetor It has two chambers with independent float chambers, which allows you to stabilize the engine when rolling the boat. The membrane fuel pump operates from the vacuum in the crank chamber without requiring an electric drive.
The quality of the mixture directly affects the resource of the piston group: a poor mixture can cause overheating and burnout of the piston, and a rich one can cause the formation of soak and loss of power. Adjustment is made by changing the position of the needle in the throttle and the quality screws of the mixture at idle.
⚠️ Warning: After a long parking period before starting, be sure to pump the fuel manually with a pear to avoid running the engine on the remnants of old fuel that could have stratified.
The fuel filter uses a mesh-filter-sludge located in the fuel system, and regular cleaning of this element prevents debris from entering the jelly carburetor.
Secrets of setting up a carburetor
Experienced motorists recommend to start the tuning with fully twisted screws of quality, and then twist them on 1.5-2 revolutions, gradually adjusting the position by the sound of the engine and the exhaust color.
Reductor and propeller
The torque is transmitted to the propeller through a single-stage gearbox with conical gears, and the gear ratio is selected to provide optimal traction for glides of light boats. The propeller It has a diameter of 230 mm and a step of 260 mm, which is the standard solution for this power.
An important element of the system is the friction, which allows for gear shifting and impact loads quenching. The gear switching is smooth, but requires a clear stroke of the reverse handle. The wear of friction linings leads to slippage over time, which reduces the efficiency of movement.
The cooling system is integrated into the gearbox body, and when driving at high speeds, control of the control jet is mandatory, and the absence of a jet signals a malfunction of the pump or clogging of the water channels.
☑️ Checking the gearbox before the season
Fuel consumption and economy
Fuel consumption in the Whirlwind 20 It depends on the mode of operation and the state of the carburetor setting: on average, at full gas, the engine consumes about 10-11 liters of the mixture per hour.
It should be borne in mind that we are talking about a mixture of gasoline and oil. Oil consumption This is approximately 200 grams per full tank of the mixture, if the ratio is 1:25 or 1:30 depending on the type of oil used. The use of modern semi-synthetic oils allows you to slightly increase the intervals and reduce the smoke of the exhaust.
To calculate the range of the fishing should be laid fuel at least 30% of the planned time in the journey. Overheating or working on an enriched mixture can significantly increase the appetite of the engine.
Service and typical problems
The durability of the motor depends on the regularity of maintenance, the main procedures are the replacement of the osteoils, lubrication of the needle bearings of the crankshaft and checking the compression. Salmon are prone to aging and can pass air, which leads to sucking and impoverishment of the mixture.
A common problem is the corrosion of aluminum parts during prolonged exposure to salt water or improper storage. After each foray, the engine is recommended to be washed with fresh water.
⚠️ Attention: If there are knocks in the lower part of the engine immediately stop operation - this may indicate the destruction of the crankshaft or rod bearings.
Timely replacement of fuel hoses and pears is also included in the list of mandatory works, since rubber eventually cracks and begins to pass air.
Regular lubrication of all friction nodes and the use of a high-quality fuel mixture increase the life of the engine vortex 20 to 1500-2000 motor hours.
Comparison with modern analogues
Compared to modern Chinese and Japanese two-tacticals, Whirlwind 20 It's a great success in terms of maintenance and availability of parts, but it's a big loser in terms of weight and environmental friendliness, and modern engines are 5-7 kg lighter and have a better cylinder purging system.
However, for heavy operating conditions, where the possibility of "field" repair with a hammer and screwdriver is important, the Soviet design remains out of competition. Repairability This engine allows you to restore its performance even far from civilization.
The choice in favor of this model is often made by conservative users who appreciate the predictability of the behavior of the technique and the presence of a huge number of manuals and tips on the network.
Which gasoline is best used for vortex 20?
The best choice is the AI-92 gasoline, the AI-95 has no significant advantages, and the AI-76 can lead to detonation, the main thing is the freshness of the fuel and the absence of water impurities.
Why does the engine stop at high speeds?
Most often, this indicates a violation of the fuel supply (a jet lag is clogged, a net in the tank is clogged) or problems with the ignition system (a failure of the coil at high revs).
Can I use Whirlwind 20 on a PVC boat?
Yes, the motor can be mounted on dense inflatable boats with a hard transom, but its weight (about 40 kg) should be considered, which can be critical for light models. For PVC, lighter options are more often recommended, but Vortex 20 is quite transportable.