Kill Switch for 73 25hp Mod# 25302

[WTDucks]

Well, looks like I might be back on the water. Lower unit problem was solved by adjusting the shift lever. Imagine I might have to tear into the L/U at some point but for now its doing ok.<br /><br />I do need to install a kill switch. Being that I will be using this boat at some odd hours duck hunting, this is a safety issue I need to address. <br /><br />Motor has a push button stop. Does this stop button need to be replaced with another type of switch that is activated with break away kill lanyard? <br /><br />I do have a kill switch (not hooked up) that works in the opposite way than the push button stop if that makes sense. This kill switch works by spring activation (by going out) while the stop works by being pushed in. Can this be wired in, and if so, how would I go about doing this? <br /><br />Thank yall for the help on this motor!! Looks like Im right there on getting this ol motor ship shape. Had it out this weekend and it ran like a bat outa hell!!

 

[Hooty]

Re: Kill Switch for 73 25hp Mod# 25302

Hello Ducks,<br />Whats goin' on over in P-town.<br />Have a look at the wire going to the push button kill switch. If it's black and yellow, that's the wire you want in to. What it does is send the voltage to the p/p to ground when you push it. The other switch you have goes too ground when it springs out (when the lanyard is pulled). Tee into the black and yellow wire and connect that wire to one of the posts on the lanyard switch and the other post too an engine ground. That should ground the p/p when the lanyard is pulled and kill the engine. Check it to be sure it works and lettus know.<br /><br />Now, go hont dem ducky-birds<br /><br />c/6<br />Hooty

 

[WTDucks]

Re: Kill Switch for 73 25hp Mod# 25302

Howdy Hooty, thanks for the reply. <br /><br />If memory serves me right, boats in another location right now, the kill switch has 2 black wires that connect up to the wires running from the coils to the points. Dont remember seeing a yellow wire coming from the shut off switch. Ill check though, could be mistaken.<br /><br />Hey, your right down the road there in Coppell. Planos doing ok I guess. Sho nuff is a culture shock to a Country Boy like myself! Been here bout 5 years and I still aint used to the place. You should see the looks I get from the folks in their high falootin automobiles when they see me draggin my duck boat down the road leavin a trail of feathers in my wake!! Funny stuff. Aint got no elbow room over here!!

 

[Hooty]

Re: Kill Switch for 73 25hp Mod# 25302

Ok, your engine has points, not the cdi. I think what happens is when you push the kill button on your engine, you open the circuit between the coil and distributor. The kill switch you have closes the circuit when the lanyard is pulled so it won't work for ya. If that's the case, you can make a kill switch real easy that will work for ya. You'll needa fuse block, (Radio Shack Nr.270-739) and a piece of 1/4" X 1-1/4" brass or copper rod. Drill a 1/8" through the rod and pass a piece of strong string through it with a knot in the end. Mount the fuse block so that it's accessible and unobstructed. Cut one of the black wires going to the push-to-kill switch and wire the fuse block into that circuit. Snap the 1/4" X 1-1/4" rod into the fuse block in place of the fuse and securely attach the other end of the string to yosef. Now, if you decide to jump in the water after one of dem duck-birds, the string will pull the rod out of the fuse block, opening the circuit and killin' the engine. That's the way we did it in race boats a hunnered years ago.<br /><br />g'luck & c/6<br />Hooty

 

[WTDucks]

Re: Kill Switch for 73 25hp Mod# 25302

Thank ya Hootie. Yes this engine has points & no CID. I will make my own. Sounds pretty straight forward.

 

[Chinewalker]

Re: Kill Switch for 73 25hp Mod# 25302

Hooty's switch will NOT work for you, as you need to have an open circuit when the lanyard is in place. You add one wire to the post on each set of points. Bring it through the armature plate to the switch. If the switch is to be mounted on the boat, add a 2-prong trailer type connector for ease of motor removal. Use a switch that has a closed circuit when engaged and an open circuit when running. The open set of points will ground through the closed set of points when the switch is engaged.<br />- Scott

 

[Hooty]

Re: Kill Switch for 73 25hp Mod# 25302

Yo Chinewalker, <br />Not sayin' you're wrong but how does the present push-to-kill switch function with just two wires then?<br /><br />c/6<br />Hooty

 

[Xcusme]

Re: Kill Switch for 73 25hp Mod# 25302

What Chinewalker is saying is that both sets of points are connected with a piece of wire that leads down to one side of a Normally Closed switch. The other side of the Normally Closed switch is grounded. When the lanyard is inserted (run mode) , the switch opens and allows the points to fire the cylinders as normal. If you remove the lanyard , the switch Closes and grounds the points, killing the spark and the motor stops.<br /><br />This is the same arrangement that a pushbutton kill switch does. Two wires come to the kill switch, one from the points , the other from ground. Remember , the kill switch is an open circuit, nothing is connected inside of the switch. When you push the kill button, you cause the two wires to make contact, which grounds the points wire and the motor stops.<br /><br />In a CD2 type ignition module, the kill switch is a Normally Open type switch. Both ends of this switch are basically connected to either side of the charge capacitor inside of the module. When you push the kill button, you short both ends of the capacitor together. Since the capacitor is shorted it can't build a charge. No charge voltage...no voltage to the coils and SCR's...the motor stops.

 

[Hooty]

Re: Kill Switch for 73 25hp Mod# 25302

That's what I said in my first post but Ducks sez the switch is between the coils and points. There was no mention of the wires going to ground anywhere.<br /><br />c/6<br />Hooty

 

[Xcusme]

Re: Kill Switch for 73 25hp Mod# 25302

Now you have me interested....anyone have a circuit print??

 

[Chinewalker]

Re: Kill Switch for 73 25hp Mod# 25302

You cannot have a common wire going to both sets of points - that would short them out. You must have a seperate wire, one from EACH set of points that goes to a two pole switch. Neither wire grounds with the switch in the open position. When the switch closes, it grounds the open set of points through the closed set of points...<br /><br />Hope that clarifies things a little.<br /><br />- Scott

 

[WTDucks]

Re: Kill Switch for 73 25hp Mod# 25302

Let me see if I can describe what I have a little better. <br /><br />There are 2 sets of points and coils. One for each cylinder. There is a wire going from the points to the coil. The stop switch has 2 wires, both black, coming out of the back of the switch that connect up to the 2 individual/seperate wires for each of the point/coils for the 2 cylinders. The motor is stopped when the spring loaded button is pushed in. There does not appear to be a ground wire for the switch as there are only 2 wires coming from the stop switch and both wires connect up between the points and coil. That is unless just the fact that the switch is bolted on the housing in effect creates a ground.<br /><br />There is a circit print on the clymers manual on pg 363. Wish I had a way of attaching that page here.<br /><br />Hope I have described this a little better and clearer.

 

[Hooty]

Re: Kill Switch for 73 25hp Mod# 25302

So a single normally open switch would work.<br /><br />c/6<br />Hooty

 

[Xcusme]

Re: Kill Switch for 73 25hp Mod# 25302

OK I got it now. The Original kill switch (in the tiller handle or in the Lower Motor Cover) is a Normally Open, momentary push button. It is wired in series ,between both sets of coils/points. <br /><br />You can add a lanyard type kill switch ( it should be Normally Open in the 'Run" or normal position). Connect the 2 wires from the new switch to the 2 original wires . Example: If we were to call the 2 original wires A and B, connect 1 new wire to A, the other new wire to B. There is no polarity (plus or minus).<br /><br />When the lanyard is pulled, the lanyard switch shorts the A and B wires together and kills the ignition.

 

[Chinewalker]

Re: Kill Switch for 73 25hp Mod# 25302

Hi Ducks,<br /> There is no permanent "ground" attached to the switch itself because each set of points is alternately grounding out everytime they close. Since only one set of points is open at any given moment you can effectively ground out the open set through the closed set. You create a dead short across the points to close the circuit and shut off the motor.<br />- Scott

 

[WTDucks]

Re: Kill Switch for 73 25hp Mod# 25302

Fellas, <br /><br />I appreciate the replys. Not to sound stupid here, electricity & I dont get along very well, but if I were to follow Hooty's instuctions in the 4th reply on getting the fuse box from Radio Shack, would that do the trick? Hope so because Hooty's instructions are just downright clear as a crystal to me and easy to follow. <br /><br />Again, appreciate the info. Learned something else about that engine I didnt know before.<br /><br />Duck

 

[Hooty]

Re: Kill Switch for 73 25hp Mod# 25302

Nope, the fuse block ain't gonna work but the lanyard kill switch you've got will. <br /><br />Here's how: (No comments about the CAD program that drew it.)<br /><br />

<br /><br />c/6<br />Hooty