Soviet small mechanization of water transport gave fishermen and hunters legendary units, one of which is rightfully considered to be the most important. boat-engine LM 1This model, which is a continuation of the famous LM-9.8, is a two-stroke internal combustion engine designed to be installed on lightweight small-sized vessels. technical specifications of LM 1 It is not fading away as many owners still operate these reliable machines or are looking for parts to restore them.
The main purpose of this unit was to ensure the movement of small displacement boats with a speed of up to 15-20 kilometers per hour. Engine design It was simplified to facilitate field repairs, making it an indispensable tool in remote areas. powerplant It is required for anyone who wants to keep the equipment in working condition for many years.
In this article, we will discuss in detail the device, modifications and nuances of the operation of this iconic sample of water technology. capacity They are reference and what to look for when buying a used copy.
General information and history of model creation
Development LM 1 based on previous versions of the system, in particular LM-9.8The goal of the engineers was to create a unit that would combine enough traction to overcome the countercurrent and ease of maintenance, and the result was a model that became the standard of reliability for its time.
The motors of this family were produced in large series and were supplied not only for civilian use, but also for the needs of fishing farms and hunting bases. Two-stroke cycle The LM1 provided high torque at low speeds, which is critical for heavy boats, but like any technology of the era, the LM1 required careful laundry and a quality fuel mix.
⚠️ Note: When using old models of LM 1 you need to take into account the production of the resource of rubber seals and glands, which eventually tan and lose elasticity, which can lead to air sucking.
A distinctive feature of the series was the unification of many nodes, which allowed to repair the engine using a minimum set of tools. Carburetor system The ignition system was adapted to run on gasoline with an octane number available in any refueling column of the period.
Main technical specifications of LM 1
To understand the possibilities boat-engine LM 1 The numbers determine the choice of propeller, the type of boat and the expected speed, and the technical parameters of this model were strictly regulated by GOST, although the actual figures could vary slightly depending on the year of manufacture and the specific modification.
Below is a detailed table that reflects the key specificationWhat every owner or potential buyer should know:
| Parameter | Meaning | Unit of measurement |
|---|---|---|
| Power on the paddle shaft | 9.8 (or 10 hp depending on the measurement method) | hp |
| Cylinder displacement | 173 | cm3 |
| Diameter of the cylinder | 64 | mm |
| Piston stroke | 54 | mm |
| Maximum speeds | 4500-5000 | min |
It is important to note that engine The fuel mix and the exhaust system are directly affected by the quality of the fuel mixture, clogged channels or misconfigured carburetors can reduce the return by 20-30%, and the weight of the engine in running order is about 26-27 kilograms, making it relatively easy to install on the transom in small vessels.
Engine and system configuration
Heart. LM 1 It's a single-cylinder two-stroke engine with a crank-chamber purge, and this is a way to effectively use the crankcase volume to pre-compress the fuel-air mixture. Kneeshaft installed on ball bearings, which ensures good maintainability and the ability to withstand high radial loads.
System system cooling In the LM 1 engine, the water is drawn through a water intake in the lower unit and pumped into the cooling shirt, and after the heat is removed, the water is ejected with the exhaust through the hole in the lower unit, which also contributes to noise reduction.
- 🔧 Ignition system: Magdino-1, contactless, with ignition coil and a distributor interrupter located under the flywheel.
- ⛽ Fuel systemCarburetor K-33 (or its modifications), providing the preparation of a combustible mixture, with a float chamber and an idling system.
- 🌊 Transmission: Single-stage gearbox with reticulated gears, transmitting torque to the propeller.
- 🔄 Lubricant: Is carried out with oil added directly to gasoline in a ratio of 1:25 (for running) or 1:30-1:40 (for operation).
Special attention deserves launcherThe clutch mechanism allows switching between neutral, forward and reverse, ensuring the manoeuvrability of the vessel.
Fuel mix and resource consumption
Proper preparation of the fuel mixture is the key to a long life boat-engine LM 1Two-stroke engines do not have a separate lubrication system for the crank-shaft mechanism, so the oil is directly contained in gasoline. Using poor-quality oil or breaking proportions leads to rapid wear of bearings and bullies in the cylinder.
It is recommended to use gasoline A-76 or A-80 (according to the old classification), which corresponds to the modern AI-92. The use of high-octane fuels without correcting the angle of advance of ignition can lead to overheating. Fuel consumption at maximum load is about 5-6 liters per hour, which is an acceptable indicator for engines of this class.
⚠️ Warning: Never use pure gasoline without adding oil – this will cause a piston wedge in the cylinder after a few minutes of operation and costly repairs.
Mixing components is best done in a separate clean container, carefully stirring the mixture before pouring into the tank. lubricants All engine units.
How to store the fuel mixture?
Fuel mixture is not recommended to store for longer than 2-3 weeks, as modern oils can oxidize and lose their properties, and gasoline - evaporate, changing the octane number.
Maintenance and typical faults
Regular maintenance avoids most of the problems with LM 1The main emphasis should be on the cleanliness of the fuel system and the state of the cooling system. Sand and algae trapped in the pump can cause local overheating and deformation of the cylinder head.
Among the typical malfunctions, owners often experience a violation of spark formation or clogging of the carburetor's jellyplates, and the production of osteoils is also possible, which leads to water sucking into the gearbox or air sucking into the crankcase. Diagnostics Usually begins with a compression check and a visual inspection of the spark plug.
- 🔥 The engine won't start.: Check for sparks, the purity of the candle and the fuel flow into the cylinder. Often the problem lies in the bay of the candle or the lack of mixture in the carburetor.
- 🌡️ Overheating of the engineClean the water intake from garbage, check the pump and tightness of the hoses of the cooling system.
- 📉 Power dropCheck the condition of the exhaust windows (whether they are overgrown with soot), adjust the carburetor and make sure that the intake tract is tight.
☑️ Seasonal TA LM 1
For prevention, it is recommended to wash the cooling system with clean water after each operation, especially if the engine was running in salty or highly polluted water. water-shirt and prevent corrosion.
Modernization and tuning LM 1
Many enthusiasts do not stop at factory specifications and conduct tuning The most common improvement is to replace the standard propeller with a faster or more loadable one, depending on the task, and electronic ignition is also popular, eliminating the need to adjust the gap of the interrupter contacts.
Some craftsmen have been working on a larger piston diameter cylinder or installing exhaust lobe valves to improve cylinder filling, but these interventions are highly skilled and can reduce the lifespan. powerplant if it's not done correctly.
When tuning the exhaust system, remember that changing the geometry of the resonator can shift the resonant frequency, and the motor will lose power at working speeds instead of adding.
It is important to understand that any revision removes the warranties (if they are still relevant) and requires subsequent fine tuning of the carburetor. Power balance Reliability is a key factor in the modernization of old Soviet engines.
FAQ: Frequently asked questions
Which screw is better to put on LM 1 for a heavy boat?
For a heavy boat or full load, it is recommended to use a smaller pitch propeller, which will allow the engine to gain speed faster and get on plane without overloading the crankshaft.
Can I use modern two-stroke oil?
Yes, modern two-stroke oils (labeled TC-W3) are even better than Soviet oils, providing better lubrication, less smoke, and little to no soothing on a candle or a piston.
Why does the LM 1 engine stop at high speeds?
This is most often indicative of a fuel failure (a clogged fuel hose, filter or carburettor needle valve) or a leaky fuel tank (vacuum effect).
Where can I find LM1 parts today?
The main components and consumables (gassings, gaskets, candles, piston rings) can be found in specialized boating stores or on Internet sites, since many parts are unified with the Veteran and Moscow engines.
The LM 1 outboard motor is a time-tested design that, with proper maintenance and proper fuel mix, can serve for decades, while remaining a reliable assistant on the water.