Product Description
The Gunson G4074 Colortune Single Plug Kit offers a proven method of accurately tuning carburettor equipped petrol and LPG engines by allowing the combustion flame inside the cylinder to be viewed while the engine is running. The specially designed Colortune spark plug features a transparent glass insulator, enabling the user to monitor the flame colour and adjust the air/fuel mixture for optimum engine performance, smoother running and improved fuel economy.
A yellow flame indicates a rich mixture, a bluish white flame indicates a weak mixture, while a Bunsen blue flame confirms the correct air/fuel ratio. The kit also includes a viewing scope with an adjustable mirror, making it easier to observe the flame where access to the spark plug is restricted. Additional adaptors are available separately for alternative spark plug thread sizes.
Features and Benefits
• Transparent Colortune spark plug allows the combustion flame to be viewed during engine tuning.
• Suitable for older petrol and LPG 2 stroke and 4 stroke engines fitted with 14mm spark plugs.
• Viewing scope with adjustable mirror improves visibility in restricted engine bays.
• Helps optimise engine performance, smoother running and fuel economy.
• Includes 14mm short reach Colortune plug, hexagonal adaptor, angled cleaning brush and full operating instructions.
• Additional adaptors available separately for 18mm, 14mm long reach, 14mm tapered seat, 12mm and 10mm spark plug applications.
Workshop Notes
The Colortune has long been recognised as one of the simplest methods of accurately setting the air/fuel mixture on carburettor equipped engines. By observing the combustion flame rather than relying on guesswork, precise carburettor adjustment can be achieved, helping to improve engine performance, fuel economy and throttle response.
Important Vehicle Application
Designed for older carburettor equipped petrol and LPG engines only. This product is not suitable for most modern electronically fuel injected engines fitted with engine management systems, oxygen (lambda) sensors and catalytic converters. Modern engine management systems automatically control the air/fuel mixture, making manual adjustment with a Colortune unnecessary and potentially misleading. Please check your vehicle's suitability before purchasing.
Specification
Suitable Spark Plug Thread: 14mm Short Reach
Kit Contents: 14mm Short Reach Colortune Plug, Hexagonal Adaptor, Angled Cleaning Brush and Operating Instructions
Additional Adaptors Available: 18mm, 14mm Long Reach, 14mm Tapered Seat, 12mm and 10mm
Weight: 0.15kg
Height: 30mm
Width: 115mm
Depth: 165mm
Why Choose Gunson Tools?
For over 80 years, Gunson has been manufacturing specialist automotive diagnostic and tuning equipment trusted by professional workshops, restoration specialists and classic vehicle enthusiasts. Designed to simplify vehicle maintenance and fault diagnosis, Gunson products provide practical, reliable solutions that have become a benchmark for engine tuning and servicing.
