2 Stroke Engine Set-up & Tuning
A quick guide to setting up that go faster device on your engine! Yes the.... Carburettor. This is a very rough guide! because of different engine sizes and different types of carb's. It will vary but it´s a good starting point. Carburettors are supposed to be factory set, but more than often then not, they arn´t. The only way to find out is to run it.
2. Main needle (top end) adjustmentFuel and fire her up! Let the engine warm for about 30 sec´s at full throttle, now you are going to set the main needle valve by setting the engine at full throttle. The sound you are wanting to hear is a clear, crisp and constant sound. If the engine is "4 stroking", then it is running too rich, lean it out by screwing the main needle in (clockwise) until the engine rpm peeks, then richen it by 2 clicks, hold the nose of the aircraft up, (still on full throttle) if the engine starts to die, then you need to richen it by unscrewing (anticlockwise) by 1 to 2 clicks and check it again with the nose up. You should get to the point where the engine note should not change from the horizontal to vertical position on full throttle. There, you have just tuned the "top end", easy wasn´t it?
4. Handy TipIf you find the engine is fine with the glow lead attached, but slows dramatically or even stops as soon as you remove it, the glow plug is "cream crakered", time for a new one. The instructions that come with the engine should recommend a suitable plug to use, if not for starters try a good old "bullet proof" Enya No3 for engines up to 0.90.
5. Too Hot!If the engine has got too hot, allow it to cool down as this will affect the tuning of the engine!! You will know when you´re about there, because a well set up model engine will have the throttle response very similar to a racing car!! Instant pickup from "longish" periods of idle and a smooth return back to idle. GOOD LUCK. It sound´s a pain to do, but it's actually fairly easy, and makes flying a lot more fun with a powerful and reliable engine.
1. Engine Set-up
Assuming you have a computer radio, adjust the carburettor throw using the
"T.ADJ" setting so that the carburettor barrel is fully opened
in the carburettor housing when the throttle stick on the transmitter is
pushed fully forward in the full throttle position.
Firstly I suggest that you make all slow running (bottom end) adjustments
with the engine stopped, as the adjustment screw is generally situated very
close to the turning "razor like" propeller. Stop the engine,
make the adjustment, restart the engine, perform tests, stop the engine,
make any necessary adjustment etc. etc. etc. From full throttle chop the
engine back to idle, if the engine very slowly drops back to idle and it
cough´s, splutter´s and takes it´s time to reach full
rpm from being at tick over for 20 seconds then the bottom end or slow running
needle is set too rich. Screw it in (clockwise) by no more than a 1/8 of
a turn at a time and repeat the test. If however the engine just dies when
you open the throttle from being at tick over for 20 seconds then the bottom
end or slow running adjustment is set too lean, unscrew it (anticlockwise)
by no more than a 1/8 of a turn at a time, and repeat the test. As you do
these slow running adjustments make sure you continue to check the main
needle setting (readjust if necessary) on full throttle as described in
"2. Main needle - top end adjustment" as this will alter slightly
during the set up procedure of the bottom end.