Kill switch

[gcarter]

So I'm trying to finish wiring my panel and connecting everything to the boat. Well, I keep running into the the theory behind the kill switch!
According to a Donzi wiring schematic sent to me by Doug L (Thanks again Doug), the kill switch is connected by a green wire , outside the main Mercruiser wire run to the engine and connects to the (+) connection on the distributor. On the other end it goes to ground (black).
Ok, my questions;
1) My switch has four connections, two are normally open and two are normally closed. So it could be wired two ways. If I wired it normally closed (open when the switch is depressed) if the switch is activated, aren't I just grounding the ignition and isn't that a dead short? Isn't that harmful?
2) I also thought about wiring the ignition (purple) through the switch so that if the switch is activated the circuit would be open and kill the engine. But the switch is only rated for ten amps and I'm running two accessories (collant circ pump and fuel pump) on the ignition (purple) circuit. So obviously I can't do this. I thought about using the circuit through the switch to activate a relay to energise the ignition circuit and I like that idea. But maybe I'm thinking about this all wrong.

So would someone explain to me EXACTLY how to wire the kill switch?
Or if someone else thinks the relay idea is a good one, could someone reccomend a good relay to use?
TIA
:wavey:

[mattyboy]

why not just use the NC posts on the kill switch and break the + wire going to the coil ( or the ground wire for that matter if there's no ground voltage should not flow) if the switch is activated might need to add some wiring??? if you ran two wires back to the coil from the switch ran the feed to the coil thru it , this way if you have a problem with the switch you just by pass it and test without having to test a control relay and then the slave relay

[gcarter]

Thanks Matty!
Those are some good ideas.
:wavey:

[gcarter]

The circ and fuel pumps should be on the accessories circuit, not the ignition. Then the ignition wire can go to the shutdown switch...

The other option is to run the ignition wire to a bus bar. Connect a wire from the bus bar to the safety switch then to the coil lead. The pumps can then be connected to the bus bar. This alleviates the problem of them running when the switch is turned to the accessory position.

IMO, the fuel pump should be wired to an oil pressure switch (Delco PS-1 I believe) which will shut it off if the engine is not running..
Scott, thanks for your input. I did use a low pressure switch supplied by Holley ( although I can't seem to remember who actually made it). The switch energises when the starter solenoid is engaged, otherwise it only works when there is a certain minimum oil pressure. See left pic on #8 , it's on the other side of the oil pressure Tee.http://www.donzi.net/forums/showthread.php?t=36314
Well, later today I ran an additional 14ga. purple wire from the panel to the engine. Actually, this is a better solution since the existing purple ignition wire is only 16 ga. So the 14 ga. wire goes from the ign. switch to the pumps and an additional wire goes through the kill switch to the existing ignition wire to the coil. :wavey: