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Adjusting the carburetor is one of the most critical facets of running a nitro powered R/C vehicle. The fuel mixture is
referred to as being "rich" when there is too much fuel and "lean" when there is not enough fuel for the amount of air
entering the engine. The amount of fuel entering is adjusted with high and low speed threaded needle valves. The
low-speed needle is located in the front of the moving slide. The high-speed needle sticks straight up at the back of the
carburetor. Both have a slotted head that is used as a reference and receptacle for a flat blade screwdriver for
adjustments. The mixture is made richer by turning the needle counter-clockwise and leaner by turning clockwise. An
overly "rich" mixture will yield sluggish acceleration and performance with thick smoke from the exhaust. A "lean"
mixture can cause the engine to hesitate before suddenly acclerating briskly or in some cases lose power momentarily
after initial acceleration. A lean mixture also makes the engine operate hotter than desired and does not provide
enough lubrication for the internal engine components causing premature wear and damage. It is always advisable to
run the engine slightly rich
and
never lean
to avoid overheating and possible damage.
Required Equipment
You will need the following items to operate your new Muggy.
8 AA Alkaline batteries for the transmitter.
1 C Alkaline battery for the igniter.
Quality Model Car Fuel - preferably Team Losi Nitrotane Sport Fuel with 20% Nitro Content.
Fuel bottle.
7.2v 6 cell "Stick" battery pack for the remote starter.
Battery charger for the 7.2v 6 cell "Stick" battery pack.
AA x8
C x 1
Understanding "Rich" and "Lean" Fuel Mixture
Engine Break-In and Adjustments
Breaking-in your new engine is critical for proper performance. Failure to follow the break-in procedures can cause
damage and shortened engine life. During break-in always use the same fuel and nitro content you plan to run. The
carburetor is preadjusted at the factory and you must be familiar with the following adjustments and break-in procedure.
If you change fuel or run in dramatically different environments (hot/cold, high/low elevations, etc.) you will probably
have to adjust at least the high speed needle to prevent overheating and maintain proper performance.
Never allow
the engine to rev uncontrollably with the wheels off the ground.
Break-In Procedure
The first three tanks of fuel should be run with the high and low speed needles noticeably "rich" (see explanation
below). There should be a slight sluggishness and thick smoke when accelerating with the smoke decreasing as the
model gains speed. At speed there should still be a noticeable trail of smoke from the exhaust pipe. Run the Muggy on
a flat surface in an oval pattern. Ease into the throttle as you accelerate on the straight sections easing off as you
approach turns letting the model roll through the turn before easing back on the throttle. This will allow you to get a feel
for the steering response and handling characteristics of the truck. You can also break in the engine by placing the
truck up against a wall or fixed object and allow the engine to idle through two tanks of fuel.
Tools You Will Find Handy
In addition to the tools included with the Muggy, you will find the following both useful and in some cases necessary.
- Small flat blade and Philips screwdrivers.
- Needle nose pliers.
- Quality .050", 1/16", 5/64", 3/32", 1.5mm, 2.5mm, and 3mm hex (allen) drivers.
