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Dominick, Marine Mechanic
Category: Boat
Satisfied Customers: 1009
Experience:  25 Years Experience as Mechanic, 20 Yrs Boat Yard Owner/Mechanic, Factory Certified
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Removed the kill switch from my Merc 502 I/O to bench test

Customer Question

removed the kill switch from my Merc 502 I/O to bench test it - the "NC" (normally closed(?)) contacts seem to work fine (they pass current when kill button pushed/engaged), the NO ("normally open"(?) contacts seem to work fine (i.e., they pass current when the button is NOT pushed/engaged). I neglected to mark which of the pins I pulled the wires off of when I removed the switch - I assume I land the wires on the NC contacts, so that the circuit is "made" when the kill switch button is pushed ("lanyard attached") correct? I read that the other contacts are used on 2-stroke engines to "short" the ignition to shut it off - whereas the other one's I intend to use(?) actually serve to "close the circuit" allowing current to pass through the purple ignition wire(?).
Submitted: 1 year ago.
Category: Boat
Expert:  Tan replied 1 year ago.

Hello. My name is Tan.

You want the circuit closed when lanyard is attached. The way the switch works is ignition 12 volts flows through the switch to the ignition system. When you pull lanyard off it breaks the circuit cutting off 12 volts to the ignition system.

You are correct on the outboard it is the opposite. No connection when lanyard is attached. On out board it grounds the ignition when lanyard is removed.

Is this all you needed?