Waterproof Ignition Key Switch

Electrical and electronic topics for small boats
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Landlocked
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Waterproof Ignition Key Switch

Postby Landlocked » Wed Dec 16, 2015 10:51 am

We got caught in a storm and tons of sea spray soaked everything in the boat and console. Despite the fact I hosed the heck out of everything, I'm still trying to repair damage. Liberal application of WD-40 has now freed the [ignition] key switch, but push-to-choke does not work. [I want to buy] a high-quality, 100-percent-weatherproof three-position [key operated engine ignition control] switch [with the added function of] push-to-choke. Does anyone have a recommendation? I've found a four position model but not what I need. Thanks for any help--LL.

jimh
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Re: Waterproof Ignition Switch

Postby jimh » Fri Dec 18, 2015 11:17 am

Your best option in my opinion is likely to just buy a new OEM ignition key switch. A new OEM switch should be a simple replacement--it should either plug-in or wire-in with no modifications. I doubt that there exists any aftermarket outboard engine ignition key switch which would have particularly better tolerance of surviving heavy splashing or spraying with sea water.

Key operated switches are, in general, difficult to create with 100-percent-waterproof characteristics because they must contain some sort of slot for the key to be placed in the lock. The only way I can see to achieve 100-percent-waterproof characteristics would be to use a conventional mechanical lock and key mechanism, then link the action of the key and lock to an electrical switch that was hidden behind the panel.

The better outboard engine ignition key switches usually have the actual key mounted in a rubber cap assembly. When the key is inserted into the lock portion of the ignition key switch, the cap assembly covers the opening of the key slot. Check to see if your particular ignition key and switch are available with the key mounted in such a cap or cover assembly. Here is the ignition key for my c.1992 Evinrude engine, nicely mounted in a rubber shroud.

OMC_IgnitionKeyWithShroud.jpg
OMC_IgnitionKeyWithShroud.jpg (12.77 KiB) Viewed 6463 times
OMC ignition key mounted in rubber shroud to prevent ingress of water into ignition key switch slot

OMC figured this out a long time ago. When their ignition key is installed in this rubber shroud, it is much harder for water to get into the key slot of the ignition key switch. Also, there is a specific orientation for the ignition key switch because there is a drain designed into it to allow any water that does get in there to drain out. The switch has to be properly oriented to allow the water to drain. If you put the switch in upside down, you cancel the draining action.

You can also significantly improved the protection of the OEM switch against intrusion of seawater by changing its location or by adding a splash guard to the switch in its present location.

Another option is to abandon the OEM-style ignition key switch and create your own control system using several separate switch to perform all the function of the OEM ignition key switch. I don't really recommend this unless you were certain that the boat would continually be used in an environment where the key switch would be subject to continual exposure to seawater spray and soaking.

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Landlocked
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Re: Waterproof Ignition Key Switch

Postby Landlocked » Wed Dec 23, 2015 5:01 pm

Thanks Jim. I had hoped to find something like the Cole-Hersee sealed switch with O-rings and IP67 waterproof rating, part 9506060BP. West Marine has them in three-position and four-position models but neither have push-to-choke function. You are probably correct in that since this is only the second time I've had to replace it in the last 15 years, OEM is probably good enough. I tend to go overboard when I can. Merry Christmas--Chris

jimh
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Re: Waterproof Ignition Key Switch

Postby jimh » Wed Dec 23, 2015 9:28 pm

You could easily move the CHOKE or ENRICH function to its own switch. It does not have to be integral to the ignition key switch. Many of the Cole-Hersee ignition key switches for marine application have the push-to-choke function. They make hundred of ignition switches, so one of them must be appropriate.

You have not described for us the engine that will be connected to this switch. Ignition switches for outboard engines have many functions, perhaps not all of them immediately obvious. For a good example of outboard engine ignition key switch functions, see my article in the REFERENCE section on IGNITION SWITCH WIRING. Older outboard engines usually need a circuit on the ignition switch for their permanent-magnet alternator or magneto in order to shut off the engine, since many older outboard engines, once, started, will run all day without having a battery connected to them. The magneto circuit in the ignition switch usually shorts out the spark ignition primary circuit coming from the magneto, and that suppresses spark ignition, stopping the engine. In more modern engines, instead of a brute-force approach by shorting the alternator circuit to ground, the switch may be connected to a lower-voltage circuit in the engine management module that shuts off the spark ignition.