When looking to replace the ignition switch on your boat, be sure it’s a marine-grade switch. This ensures the switch will function under severe weather and various water conditions. You also want to make sure the marine ignition switch you install resists corrosion, especially if you will be boating in saltwater.
For that reason, your first choice should be a brass switch, like the popular Off/Run/Start ignition switch by Sierra or their conventional 2-position Off/On marine ignition switch. Switches made of polyester are water resistant but are not completely resistant to corrosion. That said, marine-grade polyester switches are ignition load rated up to 20 Amps vs. 15 Amps for brass. Polyester switches also have the advantage of being resistant to oxidation and less susceptible to electrical shorts.
A 20A has larger contacts which are capable of a higher load rating. The rating, whether it is 15A or 20A, needs to match the needs of the engine the key switch is operating. Undersizing the switch could cause premature failure of the switch or, in a worst-case scenario, overheating of the switch and potential electrical fire.
The other decision you want to make is which type of ignition switch you need. There are several marine switches to choose from:
2 Position - As mentioned above, the Off/On position is your basic (or conventional) marine ignition switch. We stock the Sierra MP39010 and Sierra MP39820-1 (which replaces the Sierra MP39820) and ship same day.
3 Position - This is the most common switch found on inboard and I/O engine applications. It represents the conventional Off/Run/Start used for most standard single key circuits.
4 Position - This type marine ignition switch is less common and is used where an additional position is needed to run accessory equipment, e.g. Off/Run/Start/Accessory. For example, boaters who listen to music for an extended period or those wanting a pure read on their engine hour meter might choose to buy this ignition switch.
3-Position & 4-Position Magneto - This type of ignition switch, Off/Run/Start & Push-to-Choke, is common in newer outboard engine applications. It applies power to multiple circuits and a path to ground for voltages returning from a Magneto circuit. The push-to-choke feature eliminates the need for a separate switch.
You can evaluate 3-position Magneto marine ignition switches here, here and here. We also stock this 4-position Magneto switch with push-to-choke and one for outboard engines without the choke circuit.
Caveat: If you are not trained in marine electrical systems, please contact a certified marine mechanic before attempting to install a marine ignition switch.
Our Pledge to You
You have no items in your shopping cart.