In the era of the heyday of Soviet water-motor sports and amateur fishing Neptune 23 This outboard motor, which was developed from earlier models, became a popular favorite, providing mobility for thousands of fishermen and hunters across the country, and, although it seemed archaic even in the 80s, was remarkably resilient and maintainable in the field.
Today, interest in this model PMZ (Perm Motor Plant) It is more of a nostalgic or purely utilitarian character, where owners inherit or acquire the equipment for a symbolic sum. Understanding the real technical capabilities and limitations of this unit is critical for those who plan to operate it on the water, not expecting miracles from the old machine, but not underestimating its potential.
In this article we will discuss in detail specificationYou will learn how fast you can expect, what the actual fuel consumption is, and what problems you can have when trying to start an "ancient" two-stroke after a long downtime.
History of creation and design features
Engine development Neptune 23 It was developed in the 1970s as a modernisation of the previous model. Neptune-MThe main goal of the engineers was to increase the power to 23 horsepower and improve the ergonomics of the control, structurally the engine was a two-stroke two-cylinder unit with crank-chamber purge, which was the standard for mass production at the time.
One of the key features was the ignition system. magdin with a switch-distributor, which over time gave way to more reliable electronic systems MBE-1 and IBE-3VThis significantly increased the stability of spark formation, especially at high revs, and reduced the dependence on the state of the interrupter contacts.
The body of the lower unit and legs were made of aluminum alloys, which provided good corrosion resistance, although it required regular lubrication. An important element of the design was a gearshift system, implemented through thrusts from the rumble to the reverse gearbox. This solution was simple, but required precise adjustment to avoid spontaneous switching on of the gear.
Interesting fact about design
The appearance of Neptune-23 changed depending on the year of release. Early models had more angular casings, and later versions received streamlined shapes, painted in the signature colors: white with blue or red stripe.
It is worth noting that cooling-system It was a closed-loop system, forced to circulate off-shore water through a pump mounted on a lower unit, which allowed for efficient heat removal even when working at full speed for long periods of time, which was critical to the life of the piston group.
Engine and fuel system
At the heart of the unit is a two-cylinder two-stroke engine with a displacement of 446 cubic centimeters. At a compression ratio of 1:6, it develops a rated power of 23 hp at 5000-5200 rpm. This configuration provides excellent traction at low and medium revs, which is ideal for moving heavy PVC boats or metal "kazak".
Fuel system based on carburetor K-33 Because the engine is two-stroke, the use of pure gasoline is strictly prohibited, which will lead to rapid cylinder blistering, the ratio of the mixture is usually 1:25 for break-in and 1:30-1:40 for full load mode, depending on the oil used.
- ⚡ Engine type: Two-stroke, gasoline, carburetor.
- ⚡ Number of cylinders: 2 (location in rows).
- ⚡ Workload: 446 cm3.
- ⚡ Cylinder diameter and stroke of the piston: 72 x 55 mm.
⚠️ Warning: Never store a full-fuel engine for more than a month, and the gasoline oxidizes and the oil precipitates, causing the carburetor to coking and the membrane to lose elasticity.
To prepare a high-quality mixture, it is recommended to use gasoline with an octane number not lower than AI-92. The use of lower octane numbers can cause detonation, which is harmful to aluminum pistons. Oil You should choose a special one for two-stroke engines with markings TC-W3 or domestic analogues of M8V, M12TP, although modern synthetic oils are preferable to reduce nagaroformation.
Use a transparent plastic bottle with a measuring scale to mix fuel, which will accurately observe the ratio of 1:30 and avoid oil overflows, which leads to candlelight and smoke.
Transmission and propeller
The torque transfer from the crankshaft to the propeller is through a conical gearbox enclosed in the lower unit. The gear ratio is 1:2, which reduces the propeller's speed and increases traction. The gearbox reverse provides three positions: forward, neutral and reverse.
The standard engine was equipped with a propeller with a diameter of 236 mm and a pitch of 260 mm. The propeller blades are saber-shaped, which reduces cavitation and increases efficiency on planing. However, for heavy boats or at full load, it is often recommended to install screws with a smaller pitch to make the engine easier to reach working speeds.
| Parameter | Meaning | Note |
|---|---|---|
| Type of gearbox | Single-stage | Conical gears |
| Transfer ratio | 1:2 | Standard for the series |
| Rotor diameter | 236 mm | Staff size |
| Screw pitch | 260 mm | Optimal for light boats |
| Number of blades | 3 | Aluminum alloy |
An important element of the transmission is safety-pinIt's a slashed when the screw hits an underwater obstacle, and it protects the gears of the gearbox and the crankshaft from breaking, and always carry a spare set of pins, because the quality of pins in Soviet times often varied.
☑️ Checking the gearbox before the season
Ignition system and electrical equipment
Electrical circuitry Neptune-23 It's simple enough, but it requires careful attention. Magdino generates the current for the spark plug and, in some versions, to power the onboard network (lights, reflectors), but the power of the generator part is limited, so you can't count on charging powerful batteries.
The most common problem is a breakdown of high-voltage wires or a crack in the ignition coil, which causes engine outages in wet weather, and diagnostics require visual inspection of the insulation and, if necessary, replacement of the wires with modern silicone wires that can withstand high temperatures.
- 🔌 Ignition plugs: A11-3 or A17B (depending on the year of release and settings).
- 🔌 Candle gap: 0.6-0.7 mm.
- 🔌 Ignition advance angle: It is controlled by the rotation of the base of the Magdino.
- 🔌 Capacitor: KE-250 (often fails when overheated).
Adjusting the angle of ignition is critical to getting maximum power. ignition causes detonation and overheating too early, power drops too late and increased fuel consumption, and adjustment should be done using a strobe or a special template mounted on the flywheel.
The secret to a stable spark
Many owners replace the regular contacts of the interrupter with imported analogues or switch to electronic ignition without contacts, which completely eliminates the need to clean and adjust the gap in the contacts.
Operation: speed, flow and management
The real speed of a boat with an engine Neptune 23 A light PVC boat with one operator can reach speeds of up to 25-28 km / h. A metal boat with two passengers and cargo will move at a speed of about 18-22 km / h. planing is possible with a total load of up to 350-400 kg.
Fuel consumption is one of the main parameters of interest to owners: in full gas (maximum speed) the engine consumes about 8-9 liters of the mixture per hour. At a cruising speed of about 70-80% of the maximum, the flow rate decreases to 5-6 liters. This is quite economical for a motor of such power and age.
⚠️ Attention! Do not use the engine for long periods at minimum speed (idle), this leads to intense gas on candles and pistons, and can also cause exhaust windows to coking.
Control is done through a humming device at the back of a lower unit, and the flow of gas and gear shifting requires a certain amount of effort to adjust to, and the mechanism for fixing the rummel in the full gas position often wears out, so it is sometimes fixed at long distances with improvised means that the humming device is not easily fixed. Not recommended by the safety regulationsIt is practiced by experienced motorists.
Maintenance and typical faults
Durability Neptune-23 The main enemy of the engine is overheating caused by clogging of cooling channels or malfunctioning of the impeller pump. At the first sign of lack of a control stream of water from the control hole, you need to turn off the engine and clean the system.
A typical malfunction is also the wear of the osteologic shaft, which leads to water entering the gearbox, which can be determined by the color of the oil (it becomes a milky emulsion), timely replacement of the osteologies will prevent corrosion of the gears of the bearings.
Regular TO should include:
- 🛠 Cleaning and adjusting the carburetor.
- 🛠 The lubrication of all friction nodes (bearings, thrusts, hinges).
- 🛠 Checking compression in cylinders (normal 8-9 kgf / cm2).
- 🛠 Cleansing water channels from salts and algae.
The main resource of the engine is clean fuel and the right ratio of oil. 90% of the breakdowns of Neptune-23 are associated with the quality of the fuel mixture and overheating.
Comparison with modern analogues and Fazit
Compared to modern two-stroke engines with a capacity of 20-25 hp, Neptune 23 It loses weight (52 kg vs. 40-45 kg in its analogues) and noise levels. Modern engines have a more advanced system of blowing cylinders, which reduces fuel consumption and exhaust toxicity. However, the Soviet engine wins in the price of parts and simplicity of construction, understandable to any garage master.
If you are looking for a motor for rare fishing trips, where reliability is important "in the field" and the ability to repair it with a hammer and tape, then Neptune 23 If comfort, low noise and no vibrations are the priority, consider modern four-stroke models.
In conclusion, this motor is a legend that deserves respect, and with proper care, it can go one season or two more, giving you the joy of water, but it's worth remembering that its time is irrevocably gone, and the miracles of worn out technology do not come.
When you conserve the engine for the winter, be sure to drain water from the cooling system. It is enough to remove the bottom pump hose or blow the system with compressed air to avoid breaking the block when the ice freezes.
What is the best gasoline for Neptune 23?
The best choice is the AI-92 gasoline. It ensures stable operation without detonation. The use of the AI-76 is possible, but it will require later ignition and lead to a decrease in power. The AI-95 is not recommended for use because of alcohol additives that can destroy the rubber elements of the carburetor of old engines.
Why does the engine stop at high speeds?
Most often, the cause lies in a violation of the fuel supply (jeeler clogged, the diaphragm of the gas pump is damaged) or in a violation of spark formation (breaking of the coil at high revs, combustion of the condenser).
Can you put Neptune 23 on an inflatable boat?
Yes, but with limitations, the boat must be stiff enough to have a transom board that can withstand the weight of the motor (52 kg) and vibration. For boats less than 3.2 meters long, this engine can be heavy and overpowered, creating a risk of transomper damage.
How often should you change the oil in the gearbox?
The oil in the gearbox is recommended to be changed once a season or after every 50-100 hours. If an emulsion (water) appears in the oil, the replacement should be made immediately, the cause of the water entering (usually glands) and replace them.