Adding a kill switch to an outboard engine

[Tomaret]

I’ve just acquired a 30 year old Suzuki DT4 outboard which has not been used at all in the last 15 years and was lightly used before that. It starts on the choke first pull, almost every time. The only downside is that it doesn‘t have a kill switch.

My limited understanding is that a kill switch comes “on” when the kill cord is removed to complete a circuit to short (interrup) the electric current to the spark club, causing the engine to cut out. There is a stop button on the throttle of the engine. Does this perform the same function (ie being momentarily on) as the kill switch and if so, can I wire the kill switch into the wiring effectively replacing and making redundant the stop button? Is there a more elegant way to do it?

TIA for any guidance.

 

[Plum]

I’ve just acquired a 30 year old Suzuki DT4 outboard which has not been used at all in the last 15 years and was lightly used before that. It starts on the choke first pull, almost every time. The only downside is that it doesn‘t have a kill switch.

My limited understanding is that a kill switch comes “on” when the kill cord is removed to complete a circuit to short (interrup) the electric current to the spark club, causing the engine to cut out. There is a stop button on the throttle of the engine. Does this perform the same function (ie being momentarily on) as the kill switch and if so, can I wire the kill switch into the wiring effectively replacing and making redundant the stop button? Is there a more elegant way to do it?

TIA for any guidance.

I fitted one of these Universal Boat Outboard Engine Motor Kill Stop Switch & Safety Tether Lanyar.vp | eBay in parallel with the existing stop switch so I could either yank on the kill-cord or just press the original stop switch.

www.solocoastalsailing.co.uk

 

[Tomaret]

I fitted one of these Universal Boat Outboard Engine Motor Kill Stop Switch & Safety Tether Lanyar.vp | eBay in parallel with the existing stop switch so I could either yank on the kill-cord or just press the original stop switch.

www.solocoastalsailing.co.uk

Thanks - that’s what I’ve bought, too.

 

[andsarkit]

I replaced the stop button on a 25 year old 4hp Johnson with a kill cord from Ebay. It works perfectly.
If you fit it in parallel to the original switch you will still need to attach the kill cord every time you use the engine. I did think of putting them in parallel but didn't want to drill another hole in the cover.
Best to check the operation of the switch first but most short out when pushed or when the clip is removed. The stop switch I removed had 3 wires but 2 were permanently connected together inside the switch.

 

[Tomaret]

I replaced the stop button on a 25 year old 4hp Johnson with a kill cord from Ebay. It works perfectly.
If you fit it in parallel to the original switch you will still need to attach the kill cord every time you use the engine. I did think of putting them in parallel but didn't want to drill another hole in the cover.
Best to check the operation of the switch first but most short out when pushed or when the clip is removed. The stop switch I removed had 3 wires but 2 were permanently connected together inside the switch.

Thanks. The idea is that I should attach the kill cord every time and use it! I think the original design was that the twist grip throttle would return to tick over if let go, stopping the prop, but I’d prefer to kill the engine completely. The stop button is in the end of the throttle and I don’t think the kill switch would fit in its place. A new hole is inevitable.

 

[VicS]

I’ve just acquired a 30 year old Suzuki DT4 outboard which has not been used at all in the last 15 years and was lightly used before that. It starts on the choke first pull, almost every time. The only downside is that it doesn‘t have a kill switch.

My limited understanding is that a kill switch comes “on” when the kill cord is removed to complete a circuit to short (interrup) the electric current to the spark club, causing the engine to cut out. There is a stop button on the throttle of the engine. Does this perform the same function (ie being momentarily on) as the kill switch and if so, can I wire the kill switch into the wiring effectively replacing and making redundant the stop button? Is there a more elegant way to do it?

TIA for any guidance.

You say 30 year old
There may be a safety lanyard switch available to fit depending on the exact age, It is listed as an optional extra for 1993 to 1995 models. Part number 37802-93931

If you have not done so already fit a new water pump impeller

.

 

[William_H]

One of our club o/b powered RIBs had a kill switch on the dash board in a very simple form easily replicated. It used a standard toggle switch.https://www.jaycar.com.au/dpdt-ip56-heavy-duty-toggle-switch/p/ST0585?pos=4&queryId=4d514145b689c35bcc5b1aa4ff2df63b However under the toggle switch fixing nut was a piece of metal plate bent up at the sides to make a fence on either side of toggle. The lanyard had a simple loop spliced into the end. The loop went over the toggle before the switch is put into the run position. Such that any pull on the lanyard flicked the toggle to stop position. But lanyard can not escape with out operating the switch.
This has the advantage that any bit of cord will do for lanyard and if necessary you can run the engine without the safety kill cord system. (which then becomes a disadvantage) ol'will

 

[Tomaret]

You say 30 year old
There may be a safety lanyard switch available to fit depending on the exact age, It is listed as an optional extra for 1993 to 1995 models. Part number 37802-93931

If you have not done so already fit a new water pump impeller

.

Thanks - I’ve got the impeller to fit when I’m down on the boat next week.

 

[PlankWalker]

If it doesn't have a kill switch, that a bonus! I just close the throttle on mine, kills it instantly.