1956 30hp kill circuit

[BoatBuoy]

I've got the flywheel off this engine and I've traced the wire from the vacuum switch to one set of points. I assume in the case of a 2-stroke runaway, this would ground one set of points, thereby killing the runaway condition. <br /><br />It seems like I remember that to create a "kill" circuit for these old engines, one set of points can be shorted to the other set of points.<br /><br />If this is true, then I can run a wire to one set of points, and tap the circuit to the vacuum switch(other set of points) and create a "kill" circuit wired to a switch at the helm.<br /><br />Any flaws in this thinking?

 

[Paul Moir]

Re: 1956 30hp kill circuit

None at all. That's exactly how it's done on later engines. If you use a standard outboard ignition switch, it'll provide two terminals that are connected together when the key is in the "Stop" position. On modern outboards you connect one to ground and the other to the kill circuit on the powerpack. But you would connect one terminal to one set of points and the other to the other terminal.<br /><br />The vacuum switch also actuates when the throttle is suddenly snapped shut, which can precipitate a run-away on these engines. Say you suddenly snap a shear pin and close the throttle down from full. On later outboards, the vaccum cutout switch is actually disabled at speeds above the "Start" throttle position.

 

[rodbolt]

Re: 1956 30hp kill circuit

and if you ever see a runaway on those old twins you will understand why that switch is there and do not dissconect it. been there done that was not pretty

 

[55Crestliner]

Re: 1956 30hp kill circuit

Please forgive me if this is highjacking, but I've been wanting to do this myself. <br />Is there a way to make a lanyard (is that the right word?) for the drivers wrist that could be tied into this type of kill switch? <br /><br />Is there a switch already available that could be wired up to the 2 wires that BoatBuoy is wanting to ground?<br /><br />Edit: I may have answered my own question, I did a search on iboats, but there are quite a few, and they all seem to have more terminals than what these old motors would need.

 

[R.Johnson]

Re: 1956 30hp kill circuit

If I understand this correctly, if you connect both set's of point's to the vacuam switch. You are going to stop the engine at idle, That is also what that switch is for. You could create a constant stall at idle speed.

 

[BoatBuoy]

Re: 1956 30hp kill circuit

R. Johnson, I won't be connecting them together at the vacuum switch. I will run one wire to a kill switch from one set of points, run another wire to the other side of the switch from the second set of points. <br /><br />I only have to physically run a wire to one set of points. The other set of points already has a wire run to it from the vacuum. I just pick it up at the vacuum and run it to the kill switch.

 

[lark2004]

Re: 1956 30hp kill circuit

yep, that's how it's done.<br /><br />There is a wiring diagram at the bottom of my shareaproject page. Just use the link in my signature.<br />P.S. I know that it's for a later model 40hp, but the wiring is almost identical.