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8. Setup
a) Engine Fine Tuning
Adjusting the main nozzle needle (full throttle mix)
• Start the engine and remove the plug connector.
• Let the engine warm up for approximately 1 min.
• Drive the model as usual.
• If the engine seems to run ‘too richly’ at full throttle (lots of white smoke, engine not running smoothly), turn the mix leaner by twisting the main nozzle needle
inwards by 1/16th of a turn until you have achieved the desired setting.
• Make sure that the mix is not too thin. A slight white smoke vane should be visible from the exhaust at all times.
For an even better performance, you can change to a fuel with up to 30% nitro methane. However, there is the danger that the engine would show
no satisfactory road performance any more if you return to a fuel with a lower nitro methane share.
If you want to permanently drive with a fuel with a high nitro methane content, we also recommend replacing the present with a thicker cylinder head
gasket to reduce compression.
If you do not reduce compression, the engine may overheat and run incorrectly!
Adjusting the idle mix adjusting screw
• Start the engine and adjust the main nozzle needle as described.
• Reduce the speed until the centrifugal clutch does not engage anymore and the wheels stop turning when you take the model off the ground.
• Leave the engine running at idle speed for approximately 10 – 15 seconds.
• While you are holding the model with your hand, drive at full throttle once briefly and strongly.
Take care not to contact moved parts!
• If the engine stalls as soon as you run at full throttle, the idle speed mix is too lean.
• Enrich the mix by unscrewing the idle mix adjustment screw by 1/16 rotations while the engine is switched off.
• Restart the engine and repeat the procedure until the speed transition from idle speed to full throttle is soft and spontaneous. A short delay in reaction is
normal.
• If the engine smokes strongly during transition from idle speed to full throttle and sounds very rough, then the mix is too rich.
• Make the mix thinner by screwing in the idle mix adjustment screw by 1/16 rotations while the engine is switched off.
• Restart the engine and repeat the procedure until the speed transition from idle speed to full throttle is soft and spontaneous. A short delay in reaction is
normal.
• Drive the model as usual in order to get a feeling of how the engine reacts to load changes.
• Modify the settings until the performance meets your expectations.
If you have performed the carburettor settings, the idle speed will change, which must be corrected by adjusting the throttle stop.
Adjusting the throttle stop screw (idle adjustment screw):
The idle speed adjusting screw regulates the idle speed via the position of the carburettor slide (the throttle stop).
• The higher the carburettor throughput, the higher the revolution speed.
• Turning the adjusting screw clockwise by one turn increases the throughput and thus the idle speed.
• Turning anti-clockwise once permits the slider to retract further and thus reduces the gap (the idle speed will reduce).
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