7
HIGH-SPEED NEEDLE
The “high-speed” needle is
sticking up from the carburetor.
This controls the fuel to air
mixture of the carburetor. The
needle is pre-set for break-in
from the factory at 4 turns out
from fully closed. Once the
engine is broken-in, the high-
speed needle would typically
run from 3-1/2 to 3-3/4 turns out
from closed, depending on the
weather, humidity and altitude
above sea level. To richen the mixture turn the needle
counterclockwise. To lean it, turn the needle clockwise.
LOW-SPEED NEEDLE
The “low-speed” needle is
located on the side of the
carburetor. It controls the
fuel mixture at low throttle
settings/idle and is preset
from the factory at 14-1/2
turns from fully closed while
holding the carburetor
open. There is a simple way
of adjusting the low-speed
needle correctly called the
“pinch test.” With the engine at idle, pinch the fuel line and
listen to how the engine speeds up or slows down. If the
engine increases its speed for about 2 or 3 seconds and then
loses speed, the needle is set correctly. If the engine loses
RPM quickly, it is set too lean and the low-speed needle
needs to be opened (counterclockwise) to richen the
mixture. Pinch again to check the mixture. If the engine takes
longer than 4 seconds to slow down, lean (clockwise) the
low-speed needle and then pinch again to check the mixture.
IDLE STOP SCREW
The “idle stop” screw is
located on the backside of
the carburetor.This increases
or decreases the idle speed
without changing the fuel
mixture. The barrel should be
approximately 1mm from
fully closed.
IMPORTANT! To insure long life and good performance from
your engine, you MUST break-in the engine. The break-in
period is critical for long life of the internal parts of the
engine. This should be done over the first 5 tanks of fuel.
Before running the engine, read the manual and watch the
assembly and engine tuning video that came with this kit.
FUELING THE WARHEAD
IMPORTANT! The Warhead features a fuel tank that holds
over 200cc of fuel! This will provide long runs between fill
ups. The drawback to this large size is that the engine may
flood due to the increased fuel pressure through the fuel
lines (siphon effect). This makes starting very difficult when
the tank is completely full. When getting ready to start the
engine, ONLY fill the Warhead tank to the “starting fuel level”
line (1/2-way). Once the engine is warmed up and running,
fill the tank to the top.
STARTING THE ENGINE
IMPORTANT! Your radio system must ALWAYS be turned
on and the transmitter antenna fully extended when running
the engine!
1. Fill the tank to the “starting fuel level” line (half-full).
2. Prime the engine - while the engine is cool you can place
your finger over the tuned pipe’s exhaust hole and pull the
recoil gently two times.
3. Attach the glow starter to the glow plug.
4. With the throttle at idle, start the engine by pulling the
recoil using short, quick pulls. DO NOT pull the recoil
starter’s string to the end. You only need 10 to 12 inches
of pull to start the engine with the throttle at idle.
Sometimes it is helpful to start the engine at around half
throttle. When the engine starts, immediately return the
throttle to idle. If this is not done the engine can over-rev and
cause engine damage.
FIXING A FLOODED ENGINE
If the engine is difficult to turn over with the recoil starter,
especially if it is brand new, loosen the glow plug a half turn
before starting the engine. This allows some compression to
escape, but the engine will still start. Make sure you tighten
the glow plug after the engine starts. If the recoil starter is still
difficult to pull, the engine is flooded - there is too much fuel
inside the engine. Remove the glow plug, then turn the truck
upside down and pull the recoil 5 or 6 times. This will clear the
engine of fuel, and you will notice the recoil pulls easier.
Replace the glow plug and repeat the starting procedure.
STOPPING THE ENGINE
Pinch the fuel line that runs to the carburetor. Pinching this line
will restrict the fuel flow and the engine will quit within a few
seconds. Never place your finger over the exhaust to stop
the engine. This could result in serious burns on your
finger. It also causes fuel to back up in the engine, making
it harder to start the next time you run your Warhead.
R
R
UNNING
UNNING
THE
THE
ENGINE
ENGINE
ENGINE
ENGINE
TUNING GUIDE
TUNING GUIDE
BARREL 1mm
FROM FULLY
CLOSED
IDLE STOP SCREW
