MegaTech MTC 7805, Owner'S Manual

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Tempest Gladiator 9
the engine running, reduce the throttle to idle speed for
about 5 seconds, then apply full throttle very briefly and
observe the engine response. If the engine accelerates
slowly with lots of smoke and liquid fuel drops (too rich
of an air-fuel mixture), turn the low speed needle valve
clockwise 1/8 of a turn at a time until the engine acceler-
ates briskly and reliably. Make sure to test the throttle
response after each adjustment to the low speed needle
valve.
When you shut down the engine, you can also see if the
low speed needle valve is set properly. When you pinch
the fuel line closed, the engine should speed up just a lit-
tle, then quit. If it quits instantly with no increase in speed,
the low speed setting is too “lean” and you must turn the
needle valve counter-clockwise. If the engine speeds up
excessively and runs for a long time, the low speed mix-
ture is too rich, and you must adjust the low speed needle
valve by turning it clockwise.
After the idle and mid-range adjustments, slowly increase
the engine speed to approximately 50% of full throttle, but
no further. Adjust the high speed needle valve so the en-
gine again runs as rich as possible (you
want it to be pro-
ducing lots of oily smoke and spitting oil droplets from
the exhaust). Again, you may need to leave the glow plug
igniter attached to keep the engine running.
Run the Tempest Gladiator on a smooth surface at low to
medium throttle setting for another tank of fuel, being
careful not to maneuver it too harshly, or use any more
than half throttle. Leave the truck body off for maximum
cooling. Leaving the glow plug igniter attached will often
allow the engine to keep running during this rich mixture
phase.
Now you may begin adjusting the
high speed needle
valve. Carefully turn the high speed needle valve in clock-
wise 1/8 of a turn at a time, which will allow the engine to
run faster and at a higher pitch sound. Your truck will start
running faster and smoother. As you become more famil-
iar with the Tempest Gladiator, you may continue to ad-
just the high speed needle valve 1/8 of a turn at a time
until maximum speed and power are produced. When the
truck starts to lose acceleration and performance, and
overheats, you have adjusted the high speed needle valve
too far (the air-fuel mixture has become too “lean”), and
you
must turn the valve out counter-clockwise to richen
the air-fuel mixture.
The optimum high speed setting (after break-in) is
achieved by first adjusting the high speed needle valve so
the vehicle runs at the highest possible straight-line speed
(without overheating), then turning the high speed needle
valve counter-clockwise 1/8 of a turn (richen the fuel-air
mixture) to give a slight safety margin.
Be patient and make the adjustments slowly, until your
Tempest Gladiator has smooth and predictable response
through the full range of throttle settings and driving con-
ditions.
Important! The engine needle valve adjustments can only
be made accurately when the truck is running on a course
or a track. NEVER run the engine with the wheels off the
ground, because it can cause damage to the engine, the
truck, and cause injury to you.
Note: If the engine does not run properly, or the adjust-
ments are difficult to make accurately, always check that
both fuel tubes between the fuel tank and engine are not
cut, cracked, or have pinholes in them.
Make sure there are no blockages or
dirt present.
Operational Reliability
We highly recommend using a fuel filter.
Always have fresh fuel, spare glow plugs, air filter
elements, and fresh batteries.
Change or clean the air filter elements often. Dust
and dirt are the primary destroyer of model en-
gines.
Changing the type of fuel or glow plug will always
have an effect on the performance and engine set-
tings, which may need to be re-adjusted to suit.
Changes in humidity, altitude, and temperature will
also have an effect on the engine’s performance
and settings.
We recommend the Megatech high perform-
ance replacement glow plug, and Megatech
“High Velocity” 25% Nitro racing fuel, available
through your hobby dealer or direct from
Megatech Replacement Parts / Tech Support