Fabrication nation

In most cases, carburettor main jets serve as fuel metering devices – odd exceptions include floatless items fitted to small engined machines and for some stationary engine roles. Makers often code jets with flow rate, an arbitrary code or, in a few rare cases, main jet bore diameter.

Unfortunately, when we acquire unknown, second-hand carburettors (separate or fitted to machines) we can’t rely on the jet/s metering accurately due to wear or some past errant owner who has opened up the jet’s