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How to Balance Twin SU Carburettors: A Step-by-Step Guide
If your classic British car runs twin SU carburettors, getting them balanced is one of the most satisfying — and most important — tuning jobs you can do. Unbalanced carbs cause rough idling, uneven throttle response, poor fuel economy and excessive wear. The good news is that with the right approach it's a straightforward afternoon job, even for a relative beginner. This guide covers the complete process for cars fitted with twin SU carburettors, including the HS, HIF and H-series types fitted to MG, Triumph, Austin Healey, Jaguar and countless... Read more...
SU Carburettor Tuning Guide
Getting Your SU Running Perfectly A correctly tuned SU carburettor is a delight — responsive, smooth, and efficient. An incorrectly tuned one can be frustrating to diagnose. The good news is that SU carburettors are designed to be adjusted with simple tools and no specialist equipment. This guide walks through the complete tuning procedure for HS and HIF series carburettors. Before starting, make sure the carburettor has been fully serviced or rebuilt with new service parts. Attempting to tune a worn carburettor is largely futile — the variables introduced by... Read more...
Which SU Carburettor Parts Fit My Classic Car?
A Quick-Reference Guide by Vehicle One of the most common questions we get asked is: "Which SU carburettor parts do I need for my car?" The answer depends on the specific carburettor fitted, which can vary even within the same vehicle model depending on the year and engine variant. This guide covers the most popular British classics and the carburettors they were typically fitted with from the factory. Once you know your carburettor type, our Major Repair Kits and individual components are all catalogued by carburettor type to make finding... Read more...
Common SU Carburettor Problems and How to Fix Them
The Most Common Faults — and What Causes Them SU carburettors are robust, long-lived units that will run for decades with minimal attention. But when something does go wrong, the symptoms can be confusing. This guide covers the faults most commonly encountered on HS and HIF series carburettors — what causes them, how to diagnose them, and what to do about it. 1. Rich Running (Black Smoke, Sooty Plugs, High Fuel Consumption) Symptoms Black smoke from the exhaust, sooty or oil-fouled spark plugs, excessive fuel consumption, rough idle, strong petrol... Read more...
How to Rebuild an SU Carburettor: Step-by-Step Guide
Everything You Need to Know Before You Start Rebuilding an SU carburettor is one of the most satisfying jobs on a classic car — and one of the most rewarding. A properly rebuilt SU will reward you with smooth, reliable running and accurate fuel delivery. The good news is that SU carburettors are elegantly simple by design, and a full rebuild is well within the capability of any home mechanic with patience and the right parts. This guide covers the rebuild process for the HS series carburettor, which is the... Read more...
How to Identify Your SU Carburettor
HS2, HS4, HIF44 — What Have You Got? If you're working on a classic British car, chances are it's fitted with an SU carburettor. SU (Skinners Union) carburettors were fitted to millions of vehicles from the 1930s through to the 1990s — from the humble Mini to the Jaguar E-Type — and understanding exactly which type you have is the essential first step before ordering any parts. This guide will walk you through how to identify your SU carburettor by type, size, and application. The SU Carburettor Family SU produced... Read more...