Choosing a power plant for a homemade boat or upgrading an existing boat often leads aquatics to series engines. Loncin 1P70FCThis model is deservedly considered the “workhorse” among low-power units, widely used in both motoblocks and as the basis for outboard “pescary” engines and homemade propellers. Its high reliability, availability of spare parts and simplicity of design make this engine a popular choice for those who value practicality.
Unlike the more severe ones, 1P70FC engine It has a compact layout, which is critical when you put a small boat on the transom, and understanding the technical features, the ignition system and the fuel equipment, allows you not only to operate the equipment efficiently, but also to perform quality maintenance on your own, and in this material we will analyze in detail what is hidden under the casing of this unit.
Technical specifications and design features
Engine. Loncin 1P70FC The letter "F" in the marking indicates precisely the horizontal location of the crankshaft, which requires the use of a gearbox or an angle conical gearbox when installed on a boat to transfer rotation to the propeller. The power of the motor usually varies between 5-6 horsepower, which is the optimal indicator for light inflatable or aluminum boats up to 3 meters in length.
An important feature of the design is a spray lubrication system that does not require an oil pump, which greatly simplifies the device and reduces the likelihood of breakdowns. Valve mechanism It is located in the cylinder head (OHV), which provides a more efficient filling of the cylinder with a fuel-air mixture compared to the lateral arrangement of the valves, which also helps to reduce noise and fuel consumption.
- 🔧 Engine type: four-stroke, OHV, 1-cylinder, air cooling.
- ⚙️ Workload: 196 cc (modifications may vary slightly).
- 🚀 Maximum power: about 4.0 - 4.5 kW (5.5 - 6.0 hp) at 3600 rpm.
- 🛢️ Oil volume: 0.6 liters (SAE 10W-30 or equivalent is recommended).
It is worth noting that the engine shaft often has a conical duct and veneer, which simplifies the installation of pulleys or coupling-coupling for connection with the gearbox. The shaft veneer Loncin 1P70FC often has a non-standard size (for example, 5 mm or 6 mm), so when making adapters or buying a gearbox, this parameter must be measured individually with a stangentzil.
⚠️ Attention: When installing the motor on the boat, make sure that the axis of rotation of the propeller is parallel to the surface of the water. The horizontal shaft of the engine requires a high-quality angular gearbox; trying to install the screw directly on the shaft without a gearbox will lead to cavitation and no thrust.
Fuel supply system and carburetor device
The heart of the fuel system in Loncin 1P70FC It's a carburetor, most commonly a PZ19 or a modification, and it's a combustible mixture that's the right way to set it up, and it's the stability of the engine at idling speeds and the maximum power output under load, and the float carburetor design, which is the standard for this kind of technology.
Adjustment is carried out by two main screws: the quality screw of the mixture (usually located deeper and touches the needle) and the screw of the amount of mixture (rests on the throttle valve). To work stable at idle, you need to warm the engine to the operating temperature. Then, rotating the quality screw, find the position at which the engine speed is maximum, after which the number screw sets the desired idling speeds.
The sequence of the primary tuning of the carburetor:1. Wrap the screw of quality of the mixture to the point (no fanaticism!).
2. Turn the screw of quality on 1.5 - 2 revolutions.
3. Start the engine and warm up for 3-5 minutes.
4. Correct the number of revolutions XX by the screw.
A common problem is clogging of jellywood when using poor-quality gasoline or prolonged downtime. Fuel filterIt is recommended to remove and blow the carburetor with compressed air, paying attention to the idle channel.
☑️ Testing of fuel system before the season
Ignition system and clearance adjustment
On the engine. Loncin 1P70FC There's an electronic magnetic flywheel ignition system (CDI) that's basically unmaintenable, but it's sensitive to spark plugs and the right gap between the coil and the flywheel's magnetic wiring.
The gap between the ignition coil and the flywheel magnet is a critical parameter. If it's too large, the spark will be weak or disappear altogether, especially at high revs. If the coil rubs against the magnet, it will damage the winding and the knot will fail. The optimal clearance is 0.3-0.5 mm.
- 🕯️ Ignition plug: The size is usually NGK BPR6ES or analogues (M14 thread, length 19 mm).
- 🔌 Candle gap: 0.7–0.8 mm (adjusted by bending the side electrode).
- 🧲 Coil gap: 0.3–0.5 mm (adjusted by loosening the coil fastening bolts).
To adjust the coil gap, it's convenient to use a folded sheet of paper from a check tape or a business card that just gives you the necessary thickness. Relax the fastening bolts of the coil, insert a gasket between the magnet and the coil, press the coil against the magnet through the gasket and tighten the bolts. After that, remove the gasket and turn the shaft manually - you should not touch anything.
What do you do if there's no spark?
If there is no spark, replace the candle with one that is known to be working, and if that doesn't work, check the mass wire that runs from the coil to the body or switch, often because of a cliff or poor contact, and if it doesn't work, the CDI module itself, which is not repairable and changes assembly, may also fail.
Maintenance and replacement of motor oil
Engine resource Loncin 1P70FC It depends on the quality and timeliness of the engine oil change, and because the lubrication is sprayed, the oil level must be strictly within the limits of the allowable, and the engine has an oil level sensor that blocks the start or silences the engine at a critically low level, protecting the knots from bullies.
The first oil replacement should be made after the first 5-8 motor hours of operation (break-in period) to remove the products of the grinding parts. Thereafter, the replacement is made every 20-50 motor hours or at the end of the season, before preservation. Use mineral or semi-synthetic oils for four-stroke air-cooled engines with a class of viscosity SAE 10W-30 or 10W-40.
| Parameter | Recommendation | Note |
|---|---|---|
| Type of oil | SAE 10W-30 / 10W-40 | For four-stroke engines |
| Volume of crankcase | 0.6 litres | Control by probe |
| First replacement | 5-8 motor-hours | After the break-in |
| Regular replacement | Every 50 m/h | Or once in a season. |
It is important not to transfuse oil above the “FULL” mark on the probe. Excess oil will cause it to be squeezed through the sapoon into the air filter and combustion chamber, which will cause smoke and coking candles. sapoon The engine must be clean to ensure normal breathing of the crankcase.
Use a long tube syringe to pump out old oil through the probe hole - it's quicker and cleaner than unscrewing a drain plug, which is often in an uncomfortable place.
Typical malfunctions and methods of their elimination
Despite reliability, there are some problems in operation: the engine may stall under load, fail to reach full speed or run unstablely, often due to air or fuel supply, and a polluted air filter is the most common cause of rich mixes and power loss.
Another common problem is vibration and noise. Since the motor is often used on homemade trans mounts, you need to regularly check the tightening of the engine mount bolts to the frame or gearbox. Vibration can lead to weakening of joints and even cracks in the metal of the frame.
- 📉 The engine is not pulling: Check the air filter, clean the carburetor, check the compression.
- 🔥 Overheating: Clean the cylinder cooling ribs of dirt and grass, check the fan (if there is a casing).
- 🔊 Engine knock: Check the oil level, tightening of the mounting bolts, the condition of the crankshaft veneer.
⚠️ Attention: If the engine makes a metal knock, immediately silence it. Operation of the engine with a knock (turning the liners or knocking the piston) will lead to the need for major repairs or replacement of the short unit.
90 percent of Loncin 1P70FC engine start-up and operation problems are solved by carburettor maintenance, candle replacement and oil level check. Don't rush to disassemble the engine, start with simple systems.
Adaptation for outboard motors: gearboxes and shafts
Use of use Loncin 1P70FC As a outboard motor is impossible without a gearbox, since the engine shaft is horizontal, and the screw must rotate in a vertical plane. The most common homemade designs using automotive main pairs (for example, from the "classic" VAZ) or specialized boat gearboxes adapted to the landing dimensions of the engine.
The important thing is to align the speeds. The engine has a maximum power of 3600 rpm, whereas the propeller is more efficient at lower rpm (2000-3000 rpm). Therefore, the gear ratio of the gearbox must be selected so that at full engine speeds the screw does not enter cavitation. Usually, a ratio of 1:1.5 to 1:2 is used.
Example of calculating the length of the lower unit:The length of the lower unit = (Trans Height) + (Spink deepening) - (Height fastening of the gearbox)
Standard transom height: 381 mm (15 inches) or 508 mm (20 inches).
When assembling the engine-reducter-shaft unit, you need to use high-quality couplings and bearing supports. The shaft coming out of the gearbox should not experience radial loads, otherwise the oils will flow quickly, and the bearings will fail. Rowshaft It must be made of stainless steel and have protection (dadewood pipe).
What is the best gasoline for the Loncin 1P70FC?
It is recommended to use unleaded gasoline AI-92 or AI-95. The fuel should be fresh (not older than 1 month in the tank). For long-term storage (more than 2 weeks), it is better to drain gasoline from the carburetor and tank, since modern additives can precipitate and clog the jelly.
Can I install an electric starter on 1P70FC?
The basic version of the 1P70FC engine is often equipped with only a manual starter. However, there are modifications with a seat for an electric starter. Installation of an electric starter on a version without it is possible, but requires replacing the crankshaft (if there is no leak) and installing a generator coil, which is economically impractical compared to buying a finished version.
Why does the engine smoke white smoke?
White smoke indicates oil burning, causes: oil spilling into the crankcase above normal, wear of oil rings or oil pouring into the air filter, and a short-term white cloud when starting a cold engine is normal moisture condensation.