switch cam control assembly 40 the auxiliary throttle assembly 36 is located in the fuel intake manifold 22 and includes a butterfly valve plate 42 a crank arm 44 a spring 46 a flexible cable 48 and linkage 50 the crank arm 42 is fixedly attached to valve plate 42 spring 46 is attached to the crank arm 44 to normally bias the valve plate 42 to the open condition of the power mode shown in fig1 the flexible cable 48 is connected between the crank arm 44 and the exhaust valve lock up mechanism 38 linkage 50 is a rigid member connected between the crank arm 44 and the micro switch cam control 40 the exhaust valve lock up mechanism 38 includes a solenoid 52 and linkage assembly 54 comprising a mounting bracket 56 fixed to the valve cam housing 58 a first crank arm 60 pivotally mounted on the mounting bracket 56 with cable 48 and the piston rod 62 of solenoid 52 connected on one end and spring loaded link 64 connected on the other end a second crank 66 arm is pivotally mounted within the cam housing with one end connected to link 64 and the other end adapted to a position locking exhaust valve 30 in an open condition the micro switch cam control assembly 40 includes a control plate 68 slidably mounted on a fixed bracket not shown control plate 68 is connected to the main engine butterfly valve 26 by linkage 70 to the auxiliary butterfly valve assembly 36 by linkage 50 and to the accelerator pedal 72 by flex cable assembly 74 a micro switch 76 is mounted on control plate 68 and.