684i B4 / TS / QS Engine Manual
more infos: www.3w-modellmotoren.com
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Use a rubber stick to start the engine. Never use your hand or fingers!
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Insure that your receiver batteries are charged and your receiver is on
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Insure that your ignition battery(s) are charged
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Insure that your transmitter is on, and that your throttle is set to low
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Insure that your plane is properly and safely anchored (use one, two, or more people if
necessary)
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Close the choke(s)
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Switch on the ignition
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Flip the propeller until the engine "pops" (starts and stops quickly)
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Wait for the propeller to stop spinning, turn off the ignition, and open the choke(s)
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Switch the ignition back on
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Flip the propeller again until the engine starts
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Warm-up the engine for at least 20 seconds
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Due to the high power and torque of the engine(s) it is not recommended to open the throttle
abruptly
Precision tuning of the carburetor
The use of a tachometer is highly recommended. And, again, never adjust the needles while the
engine is running!
1. Using the tachometer tune the engine for maximum power with the high needle (H).
2. Again using the tachometer; richen the high needle (H) until the motor runs 100-200 RPM
less than the maximum RPM. Now you are tuned slightly rich on the high needle (H).
3. Let the engine run at idle for one minute. Check to see that the idle RPM remains constant.
4. If the idle RPM drops until the engine stops; the low needle (L) is too rich. Lean the low
needle (L) until a constant idle RPM is achieved.
5. Check the transition with a quick throttle advance. The engine should not sound strained
at any time. It should sound like it is making quick steady power; without any hesitation.
6. An optimally tuned engine will feel a bit rich after a cold start. It will start to run right after
it has warmed up for approximately one minute.
