Small 2 stroke kill switches - how do they work?

[ianc1200]

A Mercury 3.3 came with the boat I bought last Autumn. It went well but there was a trick with the kill switch to make it work. Took apart and looked this week - the switch seems to ground to earth until the kill cord is in position, so disconnecting it should (I thought) make the motor work - but it didn't. Got a new switch and put it on - outboard started immediately. So am I wrong, is there something that ensures the switch is in position/is connected or the motor won't work?

 

[KevinV]

The kick-stand switch on my old Suzuki DR is a switch+diode, so shortcircuiting it doesn't work - I wonder if your kill switch works the same?

 

[Refueler]

It likely works same way as the old lawnmower stop tabs did ... strip of metal that you pressed onto top of spark plug ... they shorted the spark plug HT lead to earth.

On the O/Bd ... the lead probably goes off the coil and when you pull the Kill lead plug out - it shorts out to earth ...

 

[VicS]

A Mercury 3.3 came with the boat I bought last Autumn. It went well but there was a trick with the kill switch to make it work. Took apart and looked this week - the switch seems to ground to earth until the kill cord is in position, so disconnecting it should (I thought) make the motor work - but it didn't. Got a new switch and put it on - outboard started immediately. So am I wrong, is there something that ensures the switch is in position/is connected or the motor won't work?

That's how they mostly work.

The parts lists show the same part for all ages and country of manufacture and other small Mercs as well.

If it has only two connections that's how yours will work, with no other mysterious features.

https://www.marineengine.com/parts/images/mercury/87823037A04.jpg