How Colortune Works; Combustion Flame Appearance - Gunson COLORTUNE G4074 Mode D'emploi

Understanding the principle by which COLORTUNE works helps in getting the best out
of it. That principle is commonly seen in action on paraffin heaters, gas cookers, or
anywhere where a fuel is burnt in air to produce heat or energy. Combustion at its
most efficient produces a clear blue flame, various other colours result from inefficient
mixtures.
Inside an internal combustion engine those same coloured flames are present though
not normally seen. With COLORTUNE fitted, in place of a sparking plug, the flame is
visible through the glass insulator and the fuel is ignited by a spark in the COLORTUNE.
This allows the user to obtain greatest engine efficiency by assessing the colour and
appearance of the flame and correcting any faults thus revealed.
Using the product could hardly be easier, fit it into a warm engine, in place of a spark
plug, and you are ready to begin.
COLORTUNE gives you a fascinating insight to the working of an engine without the
usual complexities of most other diagnostic equipment. It can provide a unique view of
the behaviour of the fuel system, in the individual cylinders, which no other equipment
can do, saving in many cases time, expense and a great deal of effort in fault diagnosis.
A gas analyser gives an average reading of all cylinders, and no diagnosis of faults or
setting errors which affect mixture distribution.
While working with this product be aware that:
• This product may be used at a wide range of engine speeds but should not be used in
an engine under load as overheating and product failure could occur. Take additional
care when using the product on an air cooled engine which has no fan assisted
cooling. On these engines limit the total test duration to 5 minutes and avoid
extended running at high rpm.
• The viewerscope supplied with this product is made from a glass reinforced heat
resistant material but will be damaged by excessive heat before the Colortune plug.
If this is damaged it serves as a clear warning of overheating. Obtain a replacement
and take more care to avoid overheating. Discontinue use if the product plating is
discoloured by heat or the glass / ceramic shows signs of damage.
The general appearance of the combustion flame when viewed through COLORTUNE is
as follows:
Yellow Indicates a fuel / air mixture which have excessive petrol content (rich).
Like a candle flame - producing more light but less heat.
Bunsen Blue Indicates a mixture which is correctly proportioned.
Whitish Blue Indicates a mixture which has less petrol content (lean)
Note: this colour is more easily seen at higher speeds.
At idle, engine instability and misfiring may occur before this weak
mixture and pale shade of blue is fully visible.

4. How Colortune works

4.a. Combustion flame appearance
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