Evolution Engines 60NX - Manual (Page 5)

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Step 2. Low-Speed Needle Adjustment, cont.
4. The low-speed fuel mixture may be too lean if
the engine stops at the lowest idle position or it
stops when the throttle is rapidly opened from
the idle position. Correct this by rotating the
SetRight adjustment bar counterclockwise in small
increments until the engine transitions smoothly
without hesitation upon opening the throttle rapidly
from idle.
Low-Speed SetRight Needle Valves
The design of the SetRight needle valve system is such
that, during normal operating conditions, the typical
user will find that the range of adjustment allowed by
the system is more than adequate for most situations.
As a matter of fact, we intended this to be used as a
tool to identify operating problems. If you find that the
range of adjustment allowed by the SetRight needle is
inadequate after your initial period of running, then a
problem in your engine system has occurred. This might
be a bad glow plug, dirty or old fuel, an air leak in the
fuel system somewhere or any number of other reasons.
Do not make any permanent adjustment range changes
to the SetRight needle system if it was once working
correctly for you and now does not. Investigate other
problems first.
However, occasionally due to atmospheric, altitudinal
or fuel conditions, you may find that the range of
adjustment built into the SetRight needle valve system
is inadequate for your needs. These conditions are rare
and easy to fix.
Low-Speed SetRight Needle Valve Correction
Should the low-speed SetRight needle valve
need to be adjusted outside the factory-
established parameters, follow these steps:
A. Loosen the setscrew found on the ring of
the SetRight assembly to which the
adjustment bar is attached.
B. Rotate the needle valve itself (small
slot-headed screw inside the blue ring of
the SetRight assembly) clockwise to lean
the mixture or counterclockwise to richen
the mixture as desired.
C. Retighten the setscrew on the ring of
the SetRight assembly and you have
re-established a new range of motion.
Why would fuel go “bad”?
The largest portion of the fuel is methanol (alcohol).
Methanol is hygroscopic; it attracts moisture. This can
cause your fuel to be contaminated with water, which will
cause poor engine performance. Additionally, the UV rays
in sunlight will eventually break down the nitromethane if
the fuel jug is stored in sunlight for long periods of time.
How can you tell when your fuel has gone “bad”?
The first indication will generally be the inability to start
the engine at previously run needle-valve settings.
Another clue might be that the engine has very poor idle,
runs but bogs down tremendously during run up and/or
will not attain the same rpms that you are used to.
How do I keep my fuel fresh?
If you have the opportunity, look for someone at a flying
field on a sunny day who has a jug of fuel that is only
1/4 full. What you may notice is that there are droplets
attached to the top and sides of the container. This is
the moisture in the air that is condensing inside the jug
because of the greenhouse effect of the semi-translucent
plastic jug. This will also occur within a metal fuel can as
the sun warms the contents.
You can combat the effects of the moisture in the air by
squeezing all the extra air from your fuel container at
the end of the day or transferring your fuel into smaller
containers as the level of the fuel is reduced in your
gallon jug. Many pilots will invest in 1/2 gallon or quart-
size containers and only bring that amount of fuel to the
field on any given day. This allows their main supply of
fuel to stay at home in a controlled storage environment,
virtually ensuring problem-free fuel.
Step 5. Attach the glow driver.
Step 6. Turn the engine over using an electric starter.
The engine should fire within seconds of applying
the starter.
Step 7. Allow the engine to idle for 30 seconds. Adjust the
throttle trim if necessary to achieve a constant
slow idle.
Step 8. With the glow driver still attached and a helper
securely holding the airplane, advance the
throttle smoothly to full throttle. The engine will
transition to full rpm.
Step 9. Reduce the throttle to idle and remove the
glow driver.
Setting the Needle Valves
The low-speed needle has a limiter that prevents
over-adjustment. If your engine starts from the above
procedure, but won’t reliably continue to run with the
glow driver removed, follow the steps below.
Step 1. High-Speed Needle Adjustment
With the engine running, advance the throttle
to full throttle while a helper securely holds your
airplane. Carefully pinch and release the fuel line
to temporarily restrict the fuel flow.
Caution: Do not reach over the propeller while
the engine is running.
Correct: If the high-speed needle adjustment
is correct, the engine will increase rpm slightly
(about 300 rpm) and then die.
Too Rich: If the engine increases a lot (1,000
rpm or greater), the high-speed needle is too rich
and must be leaned or turned clockwise.
Too Lean: If the engine doesn’t increase rpm and
simply dies, the high-speed needle is lean and
must be richened or turned counterclockwise.
Step 2. Low-Speed Needle Adjustment
The low-speed or idle needle valve, included
with the SetRight
™ assembly, is preadjusted at
the factory for best performance at close to sea
level conditions. It may be necessary to fine-tune
the low-speed adjustment using the following
procedure:
1. Start the engine and let it warm up, prior
to attempting any adjustments. Make sure
that the high-speed adjustment process is
complete before attempting to adjust the
low-speed needle valve.
2. Close the throttle slowly. You will adjust the
low-speed needle setting by rotating the
SetRight adjustment bar clockwise to lean
the engine and counterclockwise to richen the
engine.
Caution: Do not attempt to adjust the low-speed
needle valve while the engine is running.
3. The fuel mixture should be adjusted as
follows: The low-speed fuel mixture is too rich
if, when opening the throttle rapidly, the engine
emits smoke and "stutters" or "stumbles."
Correct this by rotating the SetRight adjustment
bar clockwise in small increments. Continue this
process until the engine transitions smoothly
from low rpm idle to high rpm without hesitation
upon opening the throttle rapidly.
Note that the low-speed needle adjustment range is limited,
preventing adjustment beyond the practical range.
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Low-Speed Needle Adjustment High-Speed Needle Adjustment