Sierra MP39770 Marine Ignition Starter Switch – 3-Position, Conventional, 12V/15A
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Sierra MP39770 Marine Ignition Starter Switch – 3-Position Conventional, 12V/15A
The Sierra MP39770 is a heavy-duty marine ignition starter switch built for conventional ignition systems on outboard and inboard engines. The 3-position action — Off, Ignition, and Start — delivers clean, positive control over engine startup and shutdown from the helm. A corrosion-resistant polyester housing with an inner cylinder seal keeps moisture out and eliminates the risk of shorts, making it well-suited for saltwater and high-humidity marine environments.
The 1-1/8" cylinder diameter and 7/8" mounting hole fit a wide range of marine dash panels. The 3-blade terminal layout is designed for conventional ignition wiring, and the included boot provides a finished, weather-resistant installation. Note: this switch does not include a push-to-choke function.
Key Specifications
- Part Number: 11-MP39770
- Switch Type: 3-Position (Off – Ignition – Start)
- Ignition Type: Conventional
- Voltage: 12V DC
- Current Rating: 15A
- Solenoid: 30A
- Cylinder Diameter: 1-1/8"
- Mounting Hole: 7/8"
- Terminals: 3 Blade
- Housing Material: Polyester (corrosion-resistant)
- Includes: Boot, lock and contact plate
- Push-to-Choke: Not included
Compatible Applications
- Outboard and inboard engines with conventional ignition systems
- Marine helm panels with a 7/8" mounting hole accepting a 1-1/8" cylinder switch
- 12V DC electrical systems requiring a 3-position Off/Ignition/Start switch
- Replacement for worn or damaged OEM ignition switches on conventional-ignition engines
Parts Desk Insights
The MP39770 is the right choice when your engine runs a conventional ignition system and you need a 1-1/8" cylinder switch without a push-to-choke — common on many modern outboards and inboards where choke is handled electronically or separately. The 3-blade terminal layout is the key differentiator from screw-terminal switches in this family. If your engine uses a magneto ignition instead, the Sierra MP39760 Magneto Ignition Switch is the correct fit, and includes push-to-choke. For a magneto application with a 5-screw terminal layout, the Sierra MP39100 Polyester 5-Screw Ignition Switch covers that configuration. If a brass-bodied switch is preferred, the Sierra MP39040 Brass Ignition Switch is available, though rated at 10A.
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.