The Boyer Bransden range of Analogue MKIII ignition units are being progressively changed to improved MKIV versions. The changes are designed to improve the timing stability if engine starting with a very low or variable battery voltage. The design changes are internal and do not affect the external appearance of the unit. Identified by the 'MKIV' caption on the label the new units are fully interchangeable with previously produced MK3 and MK1a units, and offer improved performance for both electric and kick start machines.
