Isolation Switch

[zdmaster2k]

We have identical isolation switches on both our motors. They are the push-to-make type. When the cord is pulled off the button pops out and, theoretically, the engine cuts. This isn't always the case however.....any ideas?

 

[Dhadley]

Re: Isolation Switch

Are you refering to the emergency cut-off switches with a lanyard on each?<br /><br />What motors do you have?<br /><br />If the motors have a magneto ignition the stop switch should make contact when the lanyard is pulled and the button pops out. When the button is in, no contact should be made.

 

[zdmaster2k]

Re: Isolation Switch

The Kill switches yes. They are mounted on the remote helm console and the button pops out when the lanyard is pulled off. We're running a 2 Stroke Evinrude 30hp and a 2 Stroke Johnson Sea Horse 25Hp

 

[umblecumbuz]

Re: Isolation Switch

Hi Bosun,<br /><br />To the best of my limited knowledge, the capacitor charge circuit (where diodes rectify the ac current to dc), supplies a positive charge to the ground side of the capacitor. This build-up is then triggered by a second circuit, using the sensor coil under the flywheel, which controls the ignition timing. The h.t. coils are powered as the capacitor discharges into them, thus producing a spark at the right time. <br /><br />One end of the capacitor is permanently connected to ground. The kill switch shorts the other end to ground, preventing a build-up of power. Hence – no pulse to the coil, therefore no spark at the plugs. <br /><br />A simple test – with engine off – which you can do without any dismantling, is to stick a pin in each of the two wires connected to the kill switch (possibly black, and black/yellow), and with the lanyard pulled off the switch (the switch in the ‘out’ position), connect a multimeter to the pins. You should get a circuit. If not, the kill switch is faulty. <br /><br />Ciao

 

[rodbolt]

Re: Isolation Switch

hello<br /> belay that pin sticking. we have enough problems with wire corroision without intentionally breaking the insulation. unplug the blk/yellow wire or the entire amphenol connector, test between the pin from the blk yellow to ground with key on and lanyard pulled. if its working you should have 0 ohms. if any more than 2 ohms it may not be working or the ground for the swtch may be bad.<br /> good luck and keep posting

 

[umblecumbuz]

Re: Isolation Switch

Bosun,<br /><br />Rodbolt's suggestion is a sound one, and easy to do. You'll need an ohmmeter of course.<br /><br />It's interesting how views and practices differ on opposite sides of the big pond. Here in the Med, where all our boating is done in salt water with high humidity, I have used the pin technique for years without any problems when testing continuity (not ht leads!)<br /> <br />Under the hood of an outboard, even one that has been neglected, I am often surprised by how good the condition of the wiring is, with little corrosion. Probably because of the engine temperature and oil haze environment. <br /><br />It's usually elsewhere on a small boat that corrosion is a big issue, which is exactly why we use the pin technique to bypass any suspect or hard-to-reach connections. I have noticed no ill-effects from doing this, and no later corrosion where the pin has been inserted. Modern plastic insulation closes up after the pin is extracted.<br /><br />In the end, you pays your money and you takes your choice!<br /><br />Ciao

 

[zdmaster2k]

Re: Isolation Switch

Thanks for your suggestions guys. They're strangly tempramental, will take some resistance readings next weekend. Don't worry about the insulation, I did it...with tape! (I know, I should get some spade connectors..)

 

[umblecumbuz]

Re: Isolation Switch

Hi again Bosun,<br /><br />A couple more thoughts.<br /><br />The kill switch itself is not grounded. It is deliberately isolated from the motor body by its insulating housing so that the ground does not rely on contact between the switch base and the motor casing. Even if the kill switch is on the console, the same should apply. <br /><br />The ground wire from the switch usually also grounds other components. Because of this, and the reasons previously given, I would not suspect a faulty ground at the motor end initially, although the console extension wires could be suspect.<br /><br />It is possible to wire in an additional on/off switch, which will function as a convenient motor stop switch, and I have seen this done. It saves yanking the lanyard on the kill switch each time you want to stop the motor, and having to reset it before you restart. Such a switch is obviously not a substitute for a kill switch, and if you take this route, the kill switch must be fully operational, and tested frequently. Personally I wouldn't do it if more than one person uses the boats. <br /><br />“Double check, and add simplicity” is a good motto for any boat owner!<br /><br />Ciao

 

[zdmaster2k]

Re: Isolation Switch

Well, its laying up time soon. I'm at the school again this saturday so will remember my multimeter. I intend to bring the switches home, get some proper connectors and WD-40 up all the metal bits. We operate on an old gravel pit in Lincolnshire, not at all like the Med, not at all glamarous, thanks again fellas.

 

[rodbolt]

Re: Isolation Switch

what year are the motors and are they remote control or tiller handle?

 

[zdmaster2k]

Re: Isolation Switch

Hi rodbolt, year is a good question, not new is the best answer I can give right now i'm afraid, I'll have a poke around under the cowl this saturday. They are both remote steering although the johnson has a second kill cord that would be used when tiller steering. We leave the lanyard on that one and the use the remote switch on the helm console