Losi LOS04002 - Manual (Page 8)

LOSI LST XXL 2 • INSTRUCTION MANUAL 8 EN
Adjusting the High Speed Needle
Turn the high-speed needle until you achieve the ideal engine temperature and
amount of exhaust smoke. The engine should have a noticeable smoke trail during
initial acceleration and fade to a minor smoke trail when the engine reaches full
throttle.
If the engine exceeds proper running temperature, 240F (116 C), richen the high-
speed needle immediately. If the engine temperature is very low considering normal
running temperature, then lean the high-speed needle.
If the high-speed needle is too lean, it will cause a high idle speed.
Adjusting the Low Speed Needle-Idle Adjustment
Turn the low-speed needle to adjust the engine idle speed. Once you have achieved
a proper idle speed, you can turn the low-speed needle by one hour in either
direction to reach the optimal engine performance. Leaning (turn in) produces a
higher idle speed. Richening (turn out) produces a lower idle speed.
Before making adjustments:
• Ensure there are no leaks or obstructions in the fuel tank, fuel tubing or the
carburetor. Any faults can affect engine operation and tuning.
• The carburetor needle is very sensitive. Adjusting the needle even 1/12 of a turn is
a significant change. Be careful when making adjustments.
High-Speed Needle (top, left
side). Close the high-speed
needle by turning it clockwise
until it stops, then turn it
counterclockwise 18 hours out
(open).
Low-Speed Needle (on the right side). Close
the low-speed needle by turning it clockwise
until it stops, then turn it counterclockwise
30 hours out (open).
Idle Needle (left, rear of
carburetor). The engine includes an
idle needle for carburetor function,
however it is not used for engine
tuning. DO NOT ADJUST THE IDLE
NEEDLE.
NOTICE: When making adjustments, only turn the needle 1/12 turn at a time.
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.
Factory Needle Settings:
Low Speed Needle: 30 hours from the bottom
High Speed Needle: 18 hours from the bottom
2 hour
1 hour
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 pre-mature wear
can occur. You want to make all carburetor adjustments in “one hour” increments.
Vehicle Tuning