The Colortune has a clear spark plug that lets you look into the combustion chamber while the engine is firing. The colour of the combustion flame tells you if the mixture is correct. With the carburettor mixture screw you can then adjust the flame colour to get the correct mixture.
The Colortune has colour charts and comprehensive instructions to carry out the job effectively. An effective flame colour - diagnosis section is included in the booklet. Comes complete with periscope for recessed plugs. "
