Instruction manual

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Troubleshooting Guide
If the Engine Does Not Start
• Check and use a new spark plug if needed.
• Check fuel lines.
• Check for proper mechanical function by
turning the engine over.
• Check that the carburetor is correctly
installed.
• Reset the needle valves to the factory
settings. High-speed 1.5 turns out, Low-
speed 4.5 turns out when the throttle barrel
is 1.5mm open.
Mechanical Faults
If the engine cannot be turned over easily
• The most likely cause is the engine is
flooded and by turning the engine over you
are trying to compress the fuel, not air.
1. Remove the spark plug.
2. Cover the cylinder head with a cloth or
paper towel and turn the propeller over to
expel all the excess fuel.
3. Replace the spark plug and try starting
again.
• A possible cause is the piston in the cylinder
is seized: loosen and unscrew the cylinder
head bolts.
1. Carefully remove the cylinder liner.
2. Visually examine the piston and cylinder
to find the possible cause of the engine’s
mechanical problem.
Mechanical repairs must ALWAYS be completed
by an authorized Horizon Hobby service center.
Maintenance
After each flying session, fully drain the fuel
from the tank.
1. Start the engine and run it until the fuel is
completely run out of the engine.
2. Try starting the engine three more times or
until it will no longer fire. This gets all the
fuel out of the engine.
If you need additional help or have any
questions, please call Horizon’s Support
Team. Horizon has trained technicians who are
qualified to answer your engine questions.
20GX2 Evolution Engines Specifications
111.5mm
107.5mm
26.5mm
36.5mm
M4 x 0.7
10.5mm
25mm
45mm
58mm
66.4mm
115.4mm
78.9mm
108mm
100.8mm
91.25mm
47.6mm
12.25mm
52.4mm
Disp 20cc Weight
Bore 30.5mm Engine Only 25.2 oz
Stroke 27.9mm Muffler 5.2 oz
Cylinder Ringed Ignition 3.5 oz
Propeller 16 x 6 @ 8,850 rpm Total 33.9 oz