Important Note

During the break-in process the engine may seem like its stalling or not running properly. This is normal; your car is not malfunctioning. It's always a good idea to get an extra glow plug (short, cold plug). It is normal to have to replace it after break-in because of the deposits left on in from the break-in process. Glow plugs are a normal item that needs replacing. Because they have such a huge influence on the way your engine runs it best to always have a few spares on hand. These are simply “break-in pains”, and with proper break-in, these symptoms will disappear. Have an extra glow plug handy incase the glow plug is ruined through the break-in process.

Purpose of Engine Break-In Procedure

The purpose of the break –in procedure is to limit and vary the engine speed. This will be accomplished by starting and stopping at different rates for using 5 tanks of fuel. Caution, high speed running is not recommended until the last and 6th tank of fuel. Doing so can permanently cause engine damage.

Be mindful of the fuel level, allowing the vehicle to run on an empty fuel tank can result in a damaged fuel plug or high engine temperatures.

 It is advised that the break-in procedure be performed in a flat and clean service since the break in procedure will be performed without the car body attached. This environment will minimize the dirt and accidental damage that may occur without the car body attached.

Breaking and throttle should be applied gently.  Sudden breaking and acceleration may cause the engine to stall and increase the chances of damaging the rc vehicle.

Before operating your nitro vehicle, check the strength of the batteries in both the receiver and controller. Weak or dead batteries can cause serious damage to your car should the car move properly due to weak batteries in the vehicle receiver or should you lose the ability to control your vehicle due to weak or dead receiver batteries.  The receiver usually require 4 AA batteries while the remote control transmitter normally require 8 AA batteries.

Follow the instruction for the first 5 tanks of fuel to perform a smooth break-in.

Starting Your Nitro Vehicle For the First Time

Install the batteries into both the transmitter and the receiver of RC vehicle.  Be sure to use only high quality alkaline batteries.  We have professional grade Duracell batteries for sale.

Always turn on the controller/transmitter first and last. This hard and fast rule will help prevent your RC from operating wildly due to receiving stray signals from another transmitter or other transmission source. Once the transmitter is turned on turn on the receiver on the RC vehicle.

Turn your transmitter wheel.  It should make the front wheels steer left and right. The wheels should then automatically return to the center when the wheel is released.  Pull back on the trigger; make sure this opens the carburetor throat. Push the trigger forward to apply the brakes.

Make sure you don’t pull out the rope to the full length.  Quick short pulls on the starter are the best technique for starting your engine.

Most air filters come moistened with oil from the factory.  Use engine or mechanical oil to moisten the filter.  Oil the air filter after before and after usage.

Lift the lid on the truck’s fuel tank and insert the fill tube. Slowly squeeze and fill the tank until its full. Be careful not to overfill the tank.

Turn on the transmitter and then the RC vehicles receiver’s switch. Attach the fully charged glow plug igniter to the glow plug. In order to aid fuel flow, hold up the front of the vehicle.  Now pull the starter with short quick pulls until the engine fires. Then remove the glow plug igniter.
Attention: If your cord becomes hard to pull then you may have flooded your engine. To clear a flooded engine, remove the glow plug and turn the car upside down. While upside-down, pull the cord a few times to clear the excess fuel. Replace the glow plug and retry. 

Tank 1

• Drive the model with the body off
• Driving Procedure: Gently pull back the throttle to ¼ position over a 2 second count. Then gently apply the brake to stop. Repeat this start and stop position until the first tank of fuel is nearly empty.
• Signals: If there is a nice trail of blue smoke from the exhaust then your engine is being lubricated and the fuel mixture is properly set. If this blue smoke is absent, richen the fuel mixture ¼ turn counterclockwise until the blue smoke is present.
• Shut off the engine by pinching the fuel line to the carburetor. Before your next tank, let the car cool down for 10-15 minutes.

Tank 2

• Driving Procedure: Gently pull back the throttle to 1/2 position over a 2 second count.Then gently apply the brake to stop.
• Repeat this start and stop position until the first tank of fuel is nearly empty. Shut off the engine by pinching the fuel line to the carburetor. Before your next tank, let the car cool down for 10-15 minutes.

Tank 3

• Driving Procedure: Gently pull back the throttle to 1/2 position over a 3 second count. Then gently apply the brake to stop. Repeat this start and stop position until the first tank of fuel is nearly empty.
• As the engine loosens
• As the break-in procedure progresses,  the idle speed may increase causing  the engine to move forward. Reduced the idle speed by turning the idle adjustment (underneath the oil filter) on the carburetor counterclockwise.
• From this point on it is no longer necessary to let the engine cool down between tanks.
• The car body can be replaced.

Tank 4

• Driving Procedure: Gently pull back the throttle to full position over a 3 second count. Then gently apply the brake to stop. Repeat this start and stop position until the first tank of fuel is nearly empty. Shut off the engine and refuel.
• Always make sure to apply throttle slowly!
• Keep your driving smooth and consistent.

Tank 5

• Driving Procedure: Gently pull back the throttle to full position over a 3 second count. Then hold for 2 seconds and gently apply the brake to stop. Repeat this start and stop position until the first tank of fuel is nearly empty. Shut off the engine and refuel.

Tank 6

• At this stage the engine is now “broken in” it is now time to tune the engine for general performance.

Tuning Your Engine Introduction

The first and foremost consideration when attempting to tune your new engine is understanding the basic parts and their functions.  Proper tuning of your engine will ensure a long lasting nitro car, truck, truggy, or buggy with maximum performance.

Tuning Your Engine: Carburetor

The main function of the carburetor is to mix the fuel and air. One this mixture is achieved, it is sent to the engine to be combusted. The Carburetor can be adjusted to control the mixture of gas/air that reaches the engine.  If you increase the amount of fuel per air mixture you are making the mix “rich” and if you decrease the amount of fuel, you are making the mixture “lean”.

An engine’s performance is dependent upon the fuel mixture. The fuel mixture is regulated by the carburetor, which is regulated by a high speed, low speed and idle speed needle.

Tune Your Engine: Important Note: Turn the mixture needles clockwise to lean the mixture and counterclockwise to richen it.

A lean fuel mixture will increase engine power. Never run an engine too lean until it cuts out or begins to stall. It could cause engine damage. Symptoms of a lean mix include:

If any of these symptoms are present richen the high speed mixture by ¼ counterclockwise turn. The engine will be slightly rich at the setting and must be returned from the setting. In order to tune for performance start with a rich setting and move leaner toward an ideal setting. Never ever tune from a lean to a rich setting. There should always be a light blue stream of smoke coming from the exhaust. You can tell an engine is running rich by observing any of the following:

• Leaning the high speed fuel mixture increases performance
• Sluggish acceleration with blue smoke coming for the exhaust tip.
• There is unburned fuel spraying from the exhaust tip.

Tune Your Engine: High Speed Fuel Mixture Adjustment

This is primary fuel mixture adjustment. It is located next to the air filter, where the fuel line goes into the engine.
           
After the engine is running warmed up, gradually lean the high speed mixture by turning in 1/16 clockwise.  Make several passes with the nitro rc after each adjustment and note any changes in performance.  Continue to adjust until at least one of the following conditions exists:

Richen the fuel mixture to the optimum setting by richening the high-speed needle at least 1/8 turn counterclockwise and retest.

Tune Your Engine: Low Speed Fuel Mixture Adjustment

The low speed mixture adjustment is always performed after the high speed needle is correctly adjusted. The easiest way to adjust the low speed mixture is by doing the “pinch” test.  The valve is located where the throttle arm pivots.

 

Once the low speed needly is correctly adjusted, the engine throttle response will be very quick. Its time to adjust the idle speed.

Tune Your Engine: Idle Speed Adjustment

This spring tensioned screw is located beneath the oil filter, facing towards the front of the vehicle. In order for an engine to run, it must have enough internal intertia engine built up in the engine to continue the entire ignition cycle. Generally speaking, you want to adjust the idles speed to the slowest idle before it stalls. The key is to set the idle speed as low as possible while still maintaining reliable running characteristics. In order to do this, turn the idle screw counterclockwise to reduce the idle speed or clockwise to increase it.

Congratulations

After breaking in the engine and tuning the engine, no major adjustments to the fuel mixture are usually necessary.

TUNING This chart indicates the direction in which you should adjust the fuel mixture when faced with changing weather and other conditions. It assumes the engine is currently well tuned. You could face any combination of conditions listed in the chart; knowing which way to go with the mixture adjustments is half the battle.   Higher air temperature   Lean   Lower air temperature   Rich   Higher humidity   Lean   Lower humidity   Rich   Higher barometric pressure   Rich   Lower barometric pressure   Lean   Higher altitude   Lean   Lower altitude   Rich   Higher nitro content   Rich   Lower nitro content   Lean   Higher oil content   Lean   Lower oil content   Rich   Hotter glow plug   Rich   Colder glow plug   Lean

 

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RC Electric or Nitro Car, Buggy, Truck or Truggy Buying Guide
RC Nitro Engine Tuning Guide