Team Losi Aftershock Operation Manual page 3

Base Start-up Settings from the Factory
High Speed Needle—2 / turns out from bottom
3
4
Low Speed Needle—3 turns out from bottom
Engine Tuning
After the engine is broken in, you can tune it for optimum performance. When tuning,
it is critical that you be cautious of overheating as severe damage and premature
wear can occur. You want to make all carburetor adjustments in "one hour"
increments.
Low Speed Adjustment
The low-speed adjustment affects the idle and slightly off idle performance. The
optimum setting allows the motor to idle for at least 8−10 seconds. The model
should then accelerate with a slight amount of sluggishness and a noticeable
amount of smoke. The simplest way to check this is to make sure the engine has
been warmed up and let the engine idle for 8−10 seconds. If the low-speed mixture
is so far off that the engine won't stay running this long, turn the idle stop screw
clockwise, increasing the idle speed. With the engine at idle, pinch and hold the fuel
line near the carburetor, cutting off the flow of fuel, and listen closely to the engine
rpm (speed). If the low-speed needle is set correctly, the engine speed will increase only slightly and then die. If the engine
increases several hundred rpm before stopping, the low-speed needle is too rich. Lean the mixture by turning the needle
clockwise one hour and trying again. If the engine speed does not increase but simply dies, the needle is too lean and
needs to be richened up by turning the needle counterclockwise one hour before trying again. After you have optimized the
low-speed setting, the engine will probably be idling faster. You will have to adjust the idle stop screw counterclockwise to
slow down the engine idle speed. The engine should accelerate at a constant pace without hesitating.
Idle Speed
Needle
Slower Faster
High-Speed Needle
As you turn this clockwise
(leaner), less fuel enters
the engine. Turning it
counterclockwise (richer) allows
more fuel to enter
the engine.
Richer
High-Speed
Needle
Carb Adjustments:
Make all carburetor adjustments in one
hour increments. Imagine the slot in the
needle is the hour hand on a clock. Adjust
it as though you were moving the hour
hand from one hour to the next or previous
one.
Low-Speed Needle
As you turn this clockwise
Idle Speed Screw
(leaner), less fuel enters
As you turn this clockwise, it the engine. Turning it
increases the carburetor opening counterclockwise (richer) allows
at idle and increases idle speed.
more fuel to enter
Turning it counterclockwise
decreases the opening and idle
speed.
Richer
Leaner
Carb Opening
Page 4
High-Speed Adjustment
After initial acceleration the engine should pull at a steady rate while maintaining a two-stroke whine and a noticeable
trail of smoke. If the engine labors and is sluggish with heavy smoke, the mixture is too rich and needs to be leaned by
turning the high-speed needle clockwise in one hour increments until it runs smoothly. If the engine isn't smoking or starts
to die after acceleration, it is too lean and you must richen the mixture by turning the needle counterclockwise. Don't be
confused by the sound of the engine and the actual performance. A leaner mixture will produce an exhaust note with a
higher pitch but this does not necessarily mean improved performance, as the engine is on the verge of overheating and
may incur possible damage. Ideally you want to run the engine so that it is on the slightly rich side of optimum. This will
give you the best combination of speed and engine life.
CAUTION: The engine is too lean and overheating if it accelerates rapidly with a high-pitched scream then seems to labor,
stops smoking or loses speed. This can be caused by the terrain, atmospheric conditions or drastic altitude changes. To
avoid permanent engine damage, immediately richen the mixture by turning the high-speed needle counterclockwise at
least "two hours" and be prepared for further adjustments before running any more.
About Glow Plugs
The glow plug is like the ignition system in your automobile. The coiled element in the center of the
plug glows red hot when connected to a 1.5-volt battery (located in the igniter). This is what ignites
the fuel/air mixture when compressed in the cylinder. After the engine fires, the heat generated by
the burning fuel keeps the element hot. Common reasons for the engine not starting are the 1.5-volt
battery being weak or dead, the glow plug being wet with fuel, or the element burned out. Use a
spare glow plug to check the igniter. If the igniter makes the element glow, remove the plug from the
engine to check it in the same manner. A wet glow plug means there is excess fuel in the engine. To
eliminate this, put a rag over the head and turn the engine over a few seconds with your "Spin-Start." Reinstall the glow
plug, making sure you have the brass gasket on it. The engine should now start.
Testing the Temperature
The ideal operating temperature for the engine will vary with the air temperature but in general it should be in the 200°F
to 230°F (93.3°C to 110°C) range. A simple way to check the engine temperature is to put a few drops of water on the
top of the head/heat sink. It should take 3−5 seconds for the water to evaporate. If it boils away quickly the engine is
overheating and the high-speed needle needs to be richened (turned counterclockwise) at least "two hours." If you plan
on racing or high-speed running, there are several inexpensive handheld digital temperature gauges available.
the engine.
Leaner
Low-Speed
Needle
Page 5
DYN2494