These videos re-posted by permission of John Twist at University Motors Ltd in Ada, Michigan — offering bench, line, and MG restoration services, as well as MG education via DVDs and technical seminars, on-site and off-site. Many thanks to John for his generous contributions to the MG community. You can see all of University Motors' videos by clicking here.
Secrets of the SU Carburetter - Part 1
Video disassembly of an SU HS2 carburetor, demonstrating damper, suction chamber, spring, air piston with tapered needle, body, choke, throttle disc (butterfly), float bowl (4 moving parts). Theory of operation: fuel mixture, venturi effect, pressure differential, throttle disc, air flow speed, variable choke, acceleration enrichment, cold starting jet.
Secrets of the SU Carburetter - Part 2
Video disassembly of an SU HS2 carburetor continued: operation: float and float bowl, jet and choke operation, tapered needle, air piston breather holes, overrun valve, oil damper valve, HS4 and HS6 differences, MGB and MGC applications, HIF4, HIF44