Technical Guides
Whether you're identifying an old SU carburetter, overhauling a classic British engine, or simply trying to get the mixture right, our technical guides cover everything you need to know.
Carburetter Type Guides
Introduction to SU CarburettersHow SU carburetters work — the constant-velocity principle explained
H Type SU CarburettersThe original design, produced in greater numbers than any other SU type
HD Type SU CarburettersDiaphragm-jet evolution of the H Type for smoother fuelling
HS Type SU CarburettersThe most common SU on British classics of the 1960s and 1970s
HIF Type SU CarburettersSU's most sophisticated design with integral float chamber
Systems & Components
Maintenance & SettingsDamper oil, jet centring, mixture adjustment and tuning
SU Electric Fuel PumpsThe iconic ticking pump — how it works and how to fix it
SU Mechanical Fuel PumpsDiaphragm-type mechanical pumps used on many British engines
AED — Automatic Enrichment DeviceThermostatic cold-start enrichment, replacing the manual choke
Choke Units & Thermostatic CarburettersCold-start enrichment systems for classic SU carburetters
Practical Guides
How to Identify Your SU CarburettorDecode the type letter, bore size and date code on your carburetter
How to Rebuild an SU CarburettorStep-by-step overhaul guide from disassembly to final tune
Common Problems & FixesFlat spots, rich running, leaks and sticking pistons diagnosed
Which Parts Fit My Classic Car?Parts lookup by vehicle make, model and carburetter type
SU Carburettor Tuning GuideMixture, idle speed and synchronisation for perfect running
Balancing Twin SU CarburettorsSynchronise a pair of SUs for smooth power across the rev range
Needle Recommendations by VehicleFind the correct needle code for your make, model and engine