---
product_id: 50150788
title: "Gunson G4074 Colortune Single Plug Kit 14mm"
brand: "gunson"
price: "2568 kr"
currency: DKK
in_stock: true
reviews_count: 13
category: "Gunson"
url: https://www.desertcart.dk/products/50150788-gunson-g4074-colortune-single-plug-kit-14mm
store_origin: DK
region: Denmark
---

# Precision carburetor tuning via combustion color 14mm short reach plug & hex adaptor Fits most M14 threaded petrol engines Gunson G4074 Colortune Single Plug Kit 14mm

**Brand:** gunson
**Price:** 2568 kr
**Availability:** ✅ In Stock

## Summary

> 🔥 Tune smarter, drive farther — see the difference inside your engine!

## Quick Answers

- **What is this?** Gunson G4074 Colortune Single Plug Kit 14mm by gunson
- **How much does it cost?** 2568 kr with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.dk](https://www.desertcart.dk/products/50150788-gunson-g4074-colortune-single-plug-kit-14mm)

## Best For

- gunson enthusiasts

## Why This Product

- Trusted gunson brand quality
- Free international shipping included
- Worldwide delivery with tracking
- 15-day hassle-free returns

## Key Features

- • **Boost Mileage & Performance:** Users report up to 150% increase in fuel efficiency and smoother throttle response.
- • **See Your Engine’s Heartbeat:** Visualize combustion chamber conditions instantly for pinpoint tuning.
- • **Made in the UK, Trusted Worldwide:** British-engineered quality combining ethical sourcing with expert manufacturing.
- • **Cut the Guesswork, Tune Like a Pro:** Eliminate trial-and-error carb adjustments with direct color-based mixture feedback.
- • **Universal Fit, Pro-Level Precision:** Compatible with most petrol/LPG engines using M14 plugs, plus extra adaptors for custom fits.

## Overview

The Gunson G4074 Colortune Single Plug Kit is a precision automotive tuning tool designed for petrol and LPG engines with M14 threaded spark plugs. It enables real-time visual inspection of combustion chamber conditions through color analysis, allowing professional-grade carburetor and fuel mixture adjustments. Crafted in the UK with high-quality copper components, this kit includes a 14mm short reach plug and hexagonal adaptor, fitting most vehicles and offering optional adaptors for broader compatibility. Trusted by classic vehicle technicians and performance enthusiasts alike, it delivers measurable improvements in fuel efficiency and engine responsiveness.

## Description

The Tune-up plug for Petrol/LPG 2 and 4 stroke engines with single, twin or multiple carburettors or fuel injection systems.The original and best tool for seeing what's happening inside the combustion chamber of the petrol engine. It allows you to see the combustion and to adjust the mixture by colour. Fits most petrol engines in standard form with additional adaptors available for vehicles with alternative sized spark plugs. A British tool company based in Warwickshire, United Kingdom. Gunson Tools draws on years of experience to introduce quality products which offer real value for money. All our products are responsibly sourced both from trusted ethical partners across the world PLUS (uniquely as an automotive tool brand) our own manufacturing base in the UK. Trusted quality products like Eezi-Bleed, ColourTune, Carbalancer and Eezi-lap are just a few names within the range. Combining our British manufacturing, our years of experience and vast expertise in the automotive sector helps us achieve our aim of bringing high quality tool solutions first to market and being No.1 choice for the Classic vehicle technician

Review: The most useful automotive tool you didn't know about - Like it says, this is the most useful tool you've never heard about. It is just as necessary as a timing light. It takes the guesswork and inference out of adjusting carburetors, not just the mixture but also things like the accelerator pump shot, mixture over different rpm ranges, and so on. Instead of inferring the best settings for your carbs by doing a grid search over different sizes, and tons of road testing, this tool allows you to observe the mixture with a decent degree of precision so you can directly observe mixture patterns. I used this to adjust my SU44 dual carbs, then put it on my 22R Weber for fun, and found out that the Redline accelerator pump shot is WAY too big, and is responsible for the rich condition on that carb. There is no other way to determine an accelerator pump issue like that. This tool is the next best thing to a code reader and O2 sensor.
Review: 150% increase in milage! - I bought this to use to tune the carb on my custom motorcycle. I had changed the pipes and replaced the airbox with a velocity stack, which meant rejetting. I had gotten it tuned fairly well (I thought!) and had been riding it for about a year like that. After hearing about the Colortune, I thought I'd give it a try. Instantly it was obvious the needled needed to be adjusted, it was WAY too rich. I moved it a couple notches, got a nice blue color and put it all back together. I immediately rode better, with much better throttle response and power, but that was just based on how it felt to me. A week later I went on a road trip with the bike and when I stopped to get gas, based on the odometer I should have needed it, the take was still half full! Quick math showed I'd been getting 60 miles a gallon! In the years since I modified it, the best I ever got was 42. When I bought it, before modifications, it got 50 on the highway. I could not believe it. But three tanks later, I was getting the same results! Colortune is worth every penny. Its easy to use, and the difference in mileage and performance it made is awesome!

## Features

- Kit includes: 14mm Short reach plug and Hexagonal adaptor
- Colortune will fit most vehicles fitted with M14 threaded plugs
- Kit complete with instructions
- Extra adaptor sizes available separately, please see Gunson Part Nos G4055E (18mm), G4055D (14mm long reach), G4055C (14mm tapered seat), G4055B (12mm), G4055A (10mm)
- The complete Colortune kit is also available with the following adaptors G4171 (with 12mm Colortune Plug), G4172 (with 10mm Colortune Plug)
- Automotive Tool

## Technical Specifications

| Specification | Value |
|---------------|-------|
| ASIN | B0012MB4VE |
| Best Sellers Rank | #314,261 in Automotive ( See Top 100 in Automotive ) #1,787 in Automotive Replacement Spark Plugs |
| Brand | GUNSON |
| Core Material | Copper |
| Customer Reviews | 4.5 4.5 out of 5 stars (577) |
| Date First Available | September 30, 2011 |
| Global Trade Identification Number | 05018341740740 |
| Is Discontinued By Manufacturer | No |
| Item Weight | 5.3 ounces |
| Item model number | G4074 |
| Manufacturer | Tool Connection (EU) |
| Manufacturer Part Number | G4074 |
| Model | G4074 |
| Product Dimensions | 1.18 x 4.53 x 6.5 inches |
| Thread Size | 12 millimeters |
| Top Material Type | Copper |
| Vehicle Service Type | Car |

## Product Details

- **Brand:** GUNSON
- **Core Material:** Copper
- **Thread Size:** 12 millimeters
- **Top Material Type:** Copper
- **Vehicle Service Type:** Car

## Images

![Gunson G4074 Colortune Single Plug Kit 14mm - Image 1](https://m.media-amazon.com/images/I/710aUHECQJL.jpg)
![Gunson G4074 Colortune Single Plug Kit 14mm - Image 2](https://m.media-amazon.com/images/I/71INdVX7UEL.jpg)
![Gunson G4074 Colortune Single Plug Kit 14mm - Image 3](https://m.media-amazon.com/images/I/71LoOD2DumL.jpg)
![Gunson G4074 Colortune Single Plug Kit 14mm - Image 4](https://m.media-amazon.com/images/I/71rioNhUcxL.jpg)
![Gunson G4074 Colortune Single Plug Kit 14mm - Image 5](https://m.media-amazon.com/images/I/71uIZ6uZRUL.jpg)

## Questions & Answers

**Q: what size adaptor do i need for spark plug autolite AP63 ?**
A: It would be a good idea if you supplied the thread size on the spark plug you need info on, if you did that I could answer your question.

**Q: Using a digital caliper, i measured the threaded portion of the spark plug and got a reading of 13.80mm. do i use the 14mm size colortune kit?**
A: I would have to say yes you are correct, but I better add that just in case it is not you should check the thread pitch with guages or your caliper. Coarse thread is 2mm pitch and  fine is 1.5mm fine. If you need any more info I'll check mine

**Q: Will this tool work on a 72 Porsche engine. Or do I need adapters**
A: I used it for 25 years on a '71 VW Super Beetle with the standard 1600 engine.  It works like a charm.  Mine was bought in the 80s from an adv. in Hot VWs.  I still have the shipping bag with the nice black box.   'Never let me down.

**Q: Will this work for a 70 gmc jimmy strait 6 2barrel carb , thanks.**
A: I use this on my Mopar V8 440 from a '68 Chrysler 300.  The 14mm thread.  i recommend loosening up the plugs when the engine is cold and then (anti-seize) them back in not too tight.  You could do all 8, but, for me, I am fine with just two on each side of my split plenum intake.   ( If you have a split plenum design, check your runners on your intake so that you are really reading two from each carb side.  Pretty funny if you happen to pick all four from the same carb circuit!  For example, on RB engines, 3 and 5, 1 and 7, or 4 and 6, 1 and 8 are matched sides for a 4-barrel.  So, 1 and 3, or, 2 and 4 would work fine.)  Keep in mind the hot exhaust manifold/headers, so, pick the plugs you can get in without burning your fingers and heating up your plastic pipe (Gunson).  After your engine is warmed up and you have done your vacuum or rev range or even AFR idle, etc., switch out the plug for the Gunson.  If you can, wrap the plastic in the 1" DEI or similar heatshield.  I used the Firesleeve.  This will protect the flimsy black plastic.  And, when done - don't take too long running the engine - take off the plastic parts and plug.  Don't let heat soak kill your piece.

## Customer Reviews

### ⭐⭐⭐⭐⭐ The most useful automotive tool you didn't know about
*by B***E on December 25, 2020*

Like it says, this is the most useful tool you've never heard about. It is just as necessary as a timing light. It takes the guesswork and inference out of adjusting carburetors, not just the mixture but also things like the accelerator pump shot, mixture over different rpm ranges, and so on. Instead of inferring the best settings for your carbs by doing a grid search over different sizes, and tons of road testing, this tool allows you to observe the mixture with a decent degree of precision so you can directly observe mixture patterns. I used this to adjust my SU44 dual carbs, then put it on my 22R Weber for fun, and found out that the Redline accelerator pump shot is WAY too big, and is responsible for the rich condition on that carb. There is no other way to determine an accelerator pump issue like that. This tool is the next best thing to a code reader and O2 sensor.

### ⭐⭐⭐⭐⭐ 150% increase in milage!
*by C***D on September 4, 2020*

I bought this to use to tune the carb on my custom motorcycle. I had changed the pipes and replaced the airbox with a velocity stack, which meant rejetting. I had gotten it tuned fairly well (I thought!) and had been riding it for about a year like that. After hearing about the Colortune, I thought I'd give it a try. Instantly it was obvious the needled needed to be adjusted, it was WAY too rich. I moved it a couple notches, got a nice blue color and put it all back together. I immediately rode better, with much better throttle response and power, but that was just based on how it felt to me. A week later I went on a road trip with the bike and when I stopped to get gas, based on the odometer I should have needed it, the take was still half full! Quick math showed I'd been getting 60 miles a gallon! In the years since I modified it, the best I ever got was 42. When I bought it, before modifications, it got 50 on the highway. I could not believe it. But three tanks later, I was getting the same results! Colortune is worth every penny. Its easy to use, and the difference in mileage and performance it made is awesome!

### ⭐⭐⭐⭐⭐ Star of the show
*by C***S on May 13, 2025*

Great, a must have for tuning. Really great product.

## Frequently Bought Together

- GUNSON G4074 Colortune Single Plug Kit 14mm
- Gunson G4055B Adaptor Kit 12 mm

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*Product available on Desertcart Denmark*
*Store origin: DK*
*Last updated: 2026-01-31*