HOWIN L4-172 User manual

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HOWIN L4-172 Engine Manual

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First of all, thank you for choosing the HOWIN ENGINE series. The L4-172 is an ultra-precision four-cylinder four-stroke engine. In order to
better understand and operate your engine for superior performance, please read the operating instructions and basic precautions of this
manual before you operate the engine.
We hope this engine will bring you wonderful experience and fun.
Thank you!

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1. About your machine
Please do not disassemble the model without permission as the high speed and high temperature of the engine could injury you or or
have other negative effects.
Unless accompanied or instructed by an adult, persons under the age of 16 should not use this engine.
If the engine is transferred to others, please transfer this manual together.
WARNING: The following points may involve serious (in extreme conditions, potentially fatal) injuries.
Please keep the engine away from open flame, overheating or any place that may cause ignition as the engine fuel is
flammable.
Do not start the machine in an enclosed space. Because the mixed fuel releases carbon monoxide, a harmful gas after burning,
starting the machine in an open environment can ensure your safety.
The machine generates a lot of heat during operation. When the engine is stopped, do not touch any part of the machine with
your hands, especially the exhaust pipe and cylinder block of this machine, the excessive temperature may cause unnecessary
burns to you.

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2. Product description
The L4-172 model is a fuel-burning engine model with a complex structure and perfect functions, which is composed
of more than 100 components and is almost close to the real engine except for the scale.
Designed in 1/8 scale, the model features a high speed of 15,000 and powerful torque, providing power for 1/8
oil-operated cars and oil boats. In order to reduce the volume of the engine and run it for a long time, we have installed an
external centrifugal water pump and enlarged the inlet & drain holes to effectively dissipate heat. This engine uses a
brushed motor for an electric start.

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2.1 Product functions

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2.2 Product dimensions

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3. Basic data
Number
Name
Information
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Model
L4-172
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Form
Finished Product
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Net Weight
1200g
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Dimensions (L,W,H)
150.9*117.8*107.6mm (The width is calculated according to the
widest position of the exhaust and intake pipes.)
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Engine Type
Nitro
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Carburetor
Single Carburetor
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Displacement
17.2cc（4×4.3cc）
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Stroke
Four-stroke
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Cylinder
In-line Four-cylinder
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Practical rpm
3000-15000 rpm
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Output power
2.4 HP
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Bore
18.00mm
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Stroke
17.00mm
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Type of Cooling
Water-cooling
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Cooling Channels
External Centrifugal Water Pump
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Starting Mode
Electric Starting
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Fuel
20-25% Nitro Fuel (Premixed Finished Product)

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4. Machine start
1. Water-cooling equipment, glow plug, fuel tank and other necessary components need to be installed before
running the engine. Component parameters:
1) Water-cooling equipment: Only need an ordinary water-cooled radiator with a fan, and the size is not less than
100*100mm, otherwise the heat dissipation effect is not ideal.
2) Starting Voltage: 12V
3) Glow Plug: 1.5V
4) Fuel Tank: Over 40mL capacity
2. Add fuel after the components are installed and fill the water-cooled radiator with pure water or coolant.
3. Lightly block the air intake of the carburetor with your finger, start the motor slowly, so that the fuel enters the
cylinder, release your finger and start the motor with full force to start.
4. Please refer to the troubleshooting instructions in the manual if it fails to start.

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5. Regular cleaning & maintenance
Users need to clean and maintain the engine regularly for better use and longevity. Our company will also provide
long-term maintenance services for this product.
1. Carefully clean the dust and oil remaining on the air inlet of the carburetor. Users can install an air filter to ensure
the cleanliness of the incoming air. If the carburetor is damaged, please replace it in time as it is non-adjustable.
2. The glow plug needs to be checked regularly. Please replace it if it is found to be abnormal.
3. Pay attention to whether the water cooling equipment is operating normally. Add pure water or coolant, and the
water tank needs to be full of water.
4. Regularly check the important parts of the engine: valve clearance, valve timing, carburetor, timing position, glow
plug and cylinder pressure. Check and adjust regularly to ensure that the engine is in good condition.

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6. Precautions
1. Do not add other fuels except nitro to the fuel tank!
2. The cooling system needs to be installed before the engine starts.
3. Do not disassemble the machine, and the machine after disassembly will not enjoy the warranty!
4. Do not touch the pulley and transmission device by hand when the machine is running!
5. Pay attention to the height of liquid in the fuel tank. The fuel outlet of the fuel tank and the fuel inlet of the
carburetor should be kept at the same level (the difference should not be greater than 2cm)!
6. Be aware that the sound of the machine starting up disturbs your neighbors.
7. Note that the maximum engine speed is 15,000 rpm, and please do not exceed this speed.
8. The machine fuel is a dangerous chemical. Please keep it in a safe place.

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7. Fault maintenance
7.1 The main reason why the engine won’t start
Engine cylinder depression or air leak: The engine you received is brand new, and the cylinder liner and piston rings
are not tightly matched.
Timing adjustment: The timing error causes incorrect valve opening & closing time so that the engine will leak air and
the piston will block the valve.
Damaged glow plug or dead battery: Make sure that the glow plug is not fused and the battery has voltage before
starting the engine.
The starting motor is weak to start: Check whether the starter battery is charged. The starting motor uses a 480 motor
with a starting voltage of 12V.
Fuel not entering the carburetor: Make sure the fuel has entered the carburetor before starting the engine.

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7.2 Adjustment method of cylinder pressure reduction and air leakage
The engine you received is brand new. In order to ensure that your engine boasts a strong cylinder pressure, our
piston ring clearance is guaranteed to be within 0.03mm. However, there are errors in the various parts of metal
processing, and there may be cases where the cylinder liner and the piston ring are not tightly matched, air leakage and
cylinder pressure reduction. The treatment methods are as follows:
1. Add lubrication oil, remove the glow plug, and power up the starting motor to make the piston and piston ring
move up and down.
2. After running for one minute, tighten the glow plug, send oil to the engine, and start the engine.

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7.3 Timing adjustment method

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We specially made corresponding marks on the camshaft synchronous wheel and crankshaft synchronous wheel
for convenient adjustment of the engine timing. There is a small hole on the camshaft synchronous wheel, and the
outer edge of the crankshaft synchronous wheel has been ground.
1. Loosen the belt tensioner and the engine timing belt.
2. Rotate the crankshaft synchronous wheel to make the grinding flat of the outer edge turn upwards.
3. Rotate the camshaft synchronous wheel to make the small hole turn upwards.
4. Adjust the timing position and fix the belt tensioner (the belt does not move around more than 5MM).

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7.4 Adjust the carburetor
1. The treatment method for the fuel not entering the carburetor:
Connect the fuel inlet pipe, block the air intake of the carburetor with one hand, rotate the engine for the fuel
entering the carburetor, release the hand blocking the carburetor, and try to start.
2. Carburetor debugging
Carburetor oil needle setting: Adjust the main oil needle to the position of 3 turns or 3.5 turns, and the auxiliary oil
needle to the position of 2 turns. The intake throttle opening & closing is 1.5mm, please adjust it according to the actual
situation.
As the methanol engine passes through the glow plug, if the idle speed is too low, the glow plug temperature will
drop. Therefore, the idle speed should not be too low and cannot be rich in oil.

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8. Commitment
1.We promise to provide comprehensive after-sales maintenance services and technical guidance services for all engines.
We support repair, replacement and return for engine quality problems caused by non-human factors.
2.Please contact the HOWIN ENGINE dealer in your country or location for various components and a full set of services, or
if you purchased online, you can obtain them via the Internet. For detailed information on each component, you can
request it from your dealer by sending an e-mail.
3.If technical or usage problems arise during use, our professional team will answer you online for free.
4.If your dealer is unable to perform its technical service, our HOWIN engineering team will provide you with technical
support directly.

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Addendum: Parts List
NO.
Name
PC
NO.
Name
PC
1
Engine Block
1
21
Cam Bearing
2
2
Cylinder Liner
4
22
Piston Ring
4
3
Lifter
8
23
Valve Spring
8
4
Rocker Arm Shaft
4
24
Start Motor
1
5
Valve Seat
8
25
Axle Sleeve
1
6
Rocker
8
26
Cylinder Head Gasket
1
7
Valve
8
27
Air Valve
1
8
Camshaft
1
28
M5 Water Nozzle
1
9
Crankshaft
1
29
M6 Water Nozzle
1
10
Cam Sync Wheel
1
30
M4 Oil Nozzle
1
11
Decorative Sync Wheel
1
31
Belt Tensioner Seat
1
12
Start Sync Wheel
1
32
Carburetor Inlet Manifold
1
13
Cam Oil Seal
2
33
Water Pump
1
14
Crankshaft Oil Seal
2
34
Water Pump Vane
1
15
Valve Spring
4
35
Water Pump Shaft
1
16
Pump Oil Seal
1
36
Exhaust Pipe
1
17
One-way Bearing
1
37
Connecting Rod
4
18
Axial Bearing
3
38
Bearing Shell
4
19
Pump Bearing
2
39
Belt Pulley Gasket
1
20
Crankshaft Bearing
2
40
Belt Pulley Flange
1