All You Need to Know About CISON FL4-175 Flathead Inline 4 Engine | Stirlingkit

All You Need to Know About CISON FL4-175 Flathead Inline 4 Engine | Stirlingkit

All You Need to Know About CISON FL4-175 Flathead Inline 4 Engine | Stirlingkit

Parameter description

.Brand: CISON
.Model: L4-175-F
.Cylinder: in-line four cylinder
.Displacement: 17.5cc
.Stroke: Four-stroke
.Bore: 16.7mm
.Stroke: 20mm;
.Speed: 1800-8500rpm
.Starting power: 2S-3S lithium batter
.CDI power: 2S-3S .
.Initial oil needle: 1.5 turns of main oil needle, 0.8 turns of auxiliary oil needle,
and 1.3mm of air valve

Igniter CDI


a. Please open the ejector rod / valve observation window first
b. Look at the picture on the CDI and find the first cylinder
c. Rotate the flywheel anticlockwise and observe the inlet valve of cylinder 1. After the
inlet valve is opened, continue to rotate the flywheel to the upper dead center
(compression point of the first cylinder). At this time, keep the flywheel still
d. install CDI magnet (with color) on the crankshaft pulley (foam: 27
The magnetic pole of faces Hall)
Note: the magnet installation must not protrude, otherwise it may collide with the engine
screw. (option 2: add shims when installing the pulley (27))
e. At this time, install the fixing screw of the upper belt pulley. Please do not fix the
belt pulley
f. The rotating pulley magnet triggers a hall close to the water pump. (Note: trigger can
be advanced by 15~0 °)

2. High voltage line

a. Observe the pictures on the CDI, check the cylinder sequence, and insert the high-
voltage wire accordingly.

Note: the high-voltage wire does not directly contact the spark plug. Please keep the
distance between the high-voltage wire and the spark plug less than 2mm, otherwise it may
be damaged sensor
3. Ground wire
a. The black wire on the CDI needs to be connected to the engine block to ensure the high
-voltage circuit. Otherwise the sensor will be damaged

Before preparing for operation

be careful!:
1. Forcibly starting the machine without running in may cause the starting motor to overheat and burn.
2. It is recommended to add 15ml~18ml lubricating oil to the oil pan (10w50 recommended, for special cases
1. Oil pump adjustment
a. Please connect the oil pipe correctly first
b. Please install the oil flow adjusting screw
c. Please adjust the oil flow according to the internal oil pipe from near to far (the closer to the oil
pump , the smaller the flow should be, otherwise there may be no oil in the farthest oil hole)
d. It is recommended not to install the crankcase side cover (foam No.: 04, 05) at first. During running in, observe whether there is splash of lubricating oil to facilitate flow adjustment.
2. Since the new machine has not been run in, the engine resistance will be
relatively large. Please carry out the following operations first
a. Remove spark plugs
b. Please adjust the oil pump correctly
c. When installing the starting motor, first use the DC 6-8v power supply for pressure free running in (Note: the starting motor cannot run for a long time, and this step can be ignored if a single piston ring is used)
d. After running in smoothly, install 2 spark plugs and start the motor again. If the engine can be easily driven, continue to install the remaining 2 spark plugs and run the starter again. If it can be easily driven, the cold running in is successful, Otherwise, please insert and remove the spark plug to continue running in (pay attention to lubrication during running in, and add a small amount of lubricating oil to the cylinder liner)
be careful!:
1. Forcibly starting the machine without running in may cause the starting motor to overheat and burn.
2. It is recommended to add 15ml~18ml lubricating oil to the oil pan (10w50 recommended, for special cases Other labels are also acceptable)

Gas distribution

How to Connect CISON FL4-175 CDI Unit?

Other Questions People Might Ask.

Video 1 is with the magnet exactly on the hall sensor, and video 2 is 5-10° advanced. As you can see, no result.
I did exactly as you told me. Cylinder 1, top dead center, exhaust valve closed and intake barely opened magnet exactly on hall sensor.
It started and ran for 7 seconds, but with the carburetor wide open. When I slowly closed it, the engine died.
A. Maybe it's the compression? Turning it by hand feels like it has ok compression.
Would it help to put o-rings in the pistons, instead of the metal rings?
B. Setting for the carburetor in the instructions must be off because it's very rich. If I close them completely, it tries to start.
I know it doesn't make sense.
C. Is it better with 2 head gaskets?
D. I noticed that all 4 spark plugs fire when the magnet comes close to the hall sensor. Is it normal?
E. How much oil does it need and what type? I put 36cc 10w40

Stirlingkit Reply:

First, the magnet cannot be on the Hall, so the ignition time should be much earlier. I don't know if the advance 5-10 you said is the advance of the magnet on the basis of the Hall or the advance of the ignition time after returning to 0. I think the valve should be wiped first. When the intake valve is opened, continue to rotate the flywheel to see the spark plug hole, or plug a non-metallic material into it to feel whether the piston has reached the top step, that is, during the compression stroke. Or make a mark in other places, and then screw on the spark plug and igniter high pressure cap. At this time, loosen the fixing screw of the pulley and rotate the pulley (the crankshaft flywheel does not move) until the high pressure cap of one cylinder shows a high pressure spark, which can be triggered repeatedly. 2 times confirmed that it is the spark of a cylinder. At this time, the ignition angle is 0°. At this time, the pulley can be adjusted to retreat 5-10° counterclockwise, which is equal to the advance of the igniter angle by the corresponding angle.
a. At this time, fix the pulley not to rotate, lock the pulley screw, and turn the flywheel by hand
b. Check whether the scale marked before the flywheel is consistent with the set ignition time.
c. Check whether the pulley is stuck by the Hall mounting screw (sometimes this may cause the pulley to move) At this point, the ignition and debugging have been delayed.
Second, the exhaust is closed, continue to rotate the camshaft, will the intake valve open next?
a. If not, the setting is wrong.
b. If yes, does the intake valve begin to open immediately after the piston is at top dead center when the crankshaft is rotated? If the piston goes down more than 0.5mm before it starts to open, it means that it should be set incorrectly. It should be correct that the piston is at the top dead center, the intake valve should be slightly opened or the intake valve will begin to open when the piston descends more than 0.1mm.
Third, if conditions permit, you can replace the Zhongyang 18 carburetor test, the Zhongyang main oil needle is 3 circles, the auxiliary oil needle is 0.7 circles, and the air valve is about 1.3mm. If the original carburetor is used, the main oil needle should be 1.3-1.5 circles, the auxiliary oil needle should be 0.8 circles, and the air valve should be about 1.5mm.
Fourth, 1 piston ring is no problem to start, but using 2 piston rings or o-rings may be easier to start and stable. Judging from the video, there is no sign of any burning explosion. Can you help me with the following tests
a. Whether the carburetor has a strong suction, you can test it with your finger
b. Whether the igniter is normal, if it is normal to ignite four together occasionally, if it is always four together, it is not normal
c. Ignition angle, as I said before, it is best to make a scale on the crankshaft, and then rotate the flywheel to check
d. Carburetor: You can try to use the Zhongyang 18 carburetor to test, it may be more stable, and you know the approximate number of oil needle circles

Question 2:

Does the Cison FL4-175 have a quadruple crankshaft? Not just two bearings like the Toyan FS-L400.

Stirlingkit Reply: The crankshaft is not the same as the TOYAN L400. The crankshaft is supported at three points, two ends and the middle, the two ends are bearings, and the middle is the copper tile.

Question 3:

Your new engine cison fl4-175 is interesting, any info other than site info? I like it very much and this will be my next purchase. I have been waiting to find it in your store since you posted the video on youtube.

Stirlingkit Reply: Glad you like it, it will be an indispensable engine in the RC model world, we are building the clutch for it, as well as testing a compatible frame. As shown.

Question 4:

Could you please tell me what oil filter should I order for my Cison FL4-175? You sent me the accessory kit, but I don't think it includes the oil filter, right? In the Cison FL4-175 operating manual, it states that Cison has a free patch available to start the motor. Can I ask for a reduction ratio (33:1) please?

Stirlingkit Reply: yes. oil filter is not included in the parcel of Cison FL4-175. You can buy it here. click. and reduction ratio is 33:1.

Question 5: Can i can the replacement part of Cison FL4-175  engine?

Stirlingkit Reply: yes. You can. Pls download the Cison FL4-175 part list file and tell me the series number of the part you want. So i can solve the problem as faster as i can. click.

Question 6: I've installed the valves, cam, and pistons. I'm getting ready to button up the rest. The directions are a little confusing for some parts so I just need to spend some time double checking the details.

Question 7:Is the carburetor an updraft or downdraft carb? The pictures online show it mounted to the top of the manifold (downdraft) and so do the videos online but the instructions show the manifold upside down with the carbonator at the bottom (updraft). The engine its based off is an updraft.

Stirlingkit Reply:Regardless of suction up and down, we also have intake manifolds installed downward. The essence of the carburetor is a pipe with a control valve. It does not contain suction itself. The suction is generated by the cylinder pressure.

Question 7:There should and must be a detailed and precise description of the ignition system with the resistors, the handling of the Hall sensor, the setting/adjustment of the ignition timing, the connection of the high-voltage generator to earth - although the CDI supplied does not even have an earth cable. Furthermore, the exact engine oil filling quantity. In addition, the engine's rotational resistance is quite high due to the friction of the piston rings - the engine has not yet been run in and I am concerned about overloading/overheating the starter motor. Obtaining a replacement is again very expensive and time-consuming. What is the difference between the "old version" starter kit and the "new version", the additional spark plugs do not fit on this engine, they are too small - they are for the "mini Hogglet", for example. A precise indication of the basic/factory setting of the carburettor would also be helpful. Of course, an exploded view of the engine would be absolutely helpful.

Stirlingkit Reply:


Other blogs of CISON L4-175 engine you may also wanna read.

CISON FL4-175 FLAT HEAD ENGINE Full Review By Dennis
A Comprehensive Review on Cison FL4-175 engine by Jon | Stirlingkit
11 Practical Tips for Assembling a FL4-175 Engine Model | Stirlingkit



1 comment

  • Bernt: September 11, 2022

    Hi, how can I test the ignition system ?
    My engine will not run on gasoline, runs fine on nitro/ glow. I have checked everything, new plugs, different gas, checked timing maney times, checked spark plugs that has a spark in the fiering order, carburator has a strong suction! The onley thing I wonder are the ignitionbox ok even if it sparks the plugs ? Is there a way to test this unless I get a new one? Like to run this engine on gas.

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