1971 Evinrude 40HP outboards Service Manual, Page 38Get this manual
allowing the motor speed to increaseThe function of the cut-out switch is to short out the breaker point for the lower cylinder momentarily when crankcase sucti0n increases, preventing the bottom spark plug from firing and thus reducing motor speedThe safety switch completes the cut-out switch circuit and prevents it from operating at full throttleThe safety switch should be adjusted on its bracket so that it opens the circuit when the plunger is at the mid-pOint on the slope of the shifter lock stop See Figure 4-22An ohmmeter or test light should indicate closed circuit when the plunger is below the cam slopeThe safety switch is also part of the electrical starting CircuitIf the vacuum cut-out switch is not functioning, check
MOUNTING ADAPTER DIAPHRAGM AND PLATE GASKET