Sierra MP39780 Marine Ignition Starter Switch – 3-Position, Conventional, Compact 5/8"
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Sierra MP39780 Marine Ignition Starter Switch – 3-Position Conventional, Compact 5/8"
The Sierra MP39780 is a compact marine ignition starter switch designed for conventional ignition systems on outboard and inboard engines. The 3-position action — Off, Ignition, and Start — provides reliable helm control over engine startup and shutdown. A corrosion-resistant polyester housing with an inner seal between the cylinder lock and contact plate keeps moisture out and prevents shorts, making it a durable choice for saltwater and high-humidity environments.
The 5/8" cylinder diameter and 7/8" mounting hole make this switch a direct fit for panels designed around the compact cylinder format. The 3-screw terminal layout suits conventional ignition wiring. Note: this switch does not include a push-to-choke function or a boot — plan accordingly if your installation requires either.
Key Specifications
- Part Number: 11-MP39780
- Switch Type: 3-Position (Off – Ignition – Start)
- Ignition Type: Conventional
- Voltage: 12V DC
- Current Rating: 15A
- Solenoid: 30A
- Cylinder Diameter: 5/8"
- Mounting Hole: 7/8"
- Terminals: 3 Screw
- Housing Material: Polyester (corrosion-resistant)
- Push-to-Choke: Not included
- Boot: Not included
Compatible Applications
- Outboard and inboard engines with conventional ignition systems
- Marine helm panels with a 7/8" mounting hole designed for a 5/8" cylinder switch
- 12V DC electrical systems requiring a compact 3-position Off/Ignition/Start switch
- Direct replacement for worn or damaged OEM ignition switches on conventional-ignition engines with compact panel cutouts
Parts Desk Insights
The MP39780 is the right pick when you have a conventional ignition engine and a panel cutout sized for the smaller 5/8" cylinder format — common on older or smaller outboards where panel space is tight. No boot is included, so if your installation is exposed to spray, source a compatible boot separately or consider the Sierra MP39770, which is the 1-1/8" conventional switch that does include a boot. If your engine runs a magneto ignition rather than conventional, the Sierra MP39760 Magneto Ignition Switch is the correct fit and includes push-to-choke.
Shipping information
In-stock and OEM parts: ship same or next business day.
Locally warehoused items: ship within 1-3 business days.
Special-order items: timeline confirmed after order.
Returns & warranty
Returns & Satisfaction Guarantee
We stand firmly behind the quality of every product we sell. Your confidence matters to us — and we back it with a straightforward 30-Day Satisfaction Guarantee.
If you are not fully satisfied, you may request a return within 30 days of delivery. All returns must receive pre-approval prior to being sent back. Unauthorized returns will not be accepted.
To qualify for a return:
Item must be in new, unused condition
Product must be in its original packaging
All parts, components, hardware, manuals, and accessories must be included
Packaging must be undamaged and suitable for resale
Important:
Electronics are strictly inspected. No returns on open-box electronics. Exceptions may apply only with prior written approval. Any electronic unit that has been installed, powered, activated, or altered may not be eligible for return.
We are serious about product integrity — and equally serious about taking care of our customers. If there is ever a product issue, contact us immediately so we can make it right.
For return authorization, please contact our support team before shipping anything back.