ARCO Heavy-Duty 12V Starter Solenoid for Mercury & MerCruiser – Isolated Base | SKU 57-SW058HD
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ARCO Heavy-Duty 12V Starter Solenoid for Mercury & MerCruiser – Isolated Base
The heavy-duty version of the ARCO SW058 starter solenoid for Mercury outboard and MerCruiser stern-drive engines. This isolated base, 12-volt solenoid is built with upgraded internal components throughout — designed for engines that see high-cycle use or operate in demanding conditions where a standard solenoid is prone to premature failure. It replaces the same Mercury OEM part numbers as the SW058 but delivers significantly more durability.
Heavy-Duty Upgrades Over Standard Solenoid
- Heavy-duty coil and contact assembly with a larger contact area for better current transfer
- High-temperature housing with reduced distortion under heat
- Molded-in studs for precise, consistent contact alignment
- High-temperature coil assembly for extended service life
- One-piece moving core with solid brass stem for reliable, long-lasting operation
Features
- 12-volt, isolated base design
- Direct replacement for Mercury and MerCruiser starter solenoids
- OEM-equivalent fit — no wiring modifications required
- Replaces 2 Mercury OEM part numbers
Compatible Applications
- Replaces Mercury part numbers: 89-846070, 89-94318
- Mercury outboard engines using the above OEM references
- MerCruiser stern-drive engines using the above OEM references
Pairs Well With
- ARCO 12V Starter Solenoid for Mercury & MerCruiser – Isolated Base (SW058) – standard-duty version for the same applications
- ARCO 12V Starter Solenoid for Mercury & MerCruiser – Isolated Base (SW054)
- ARCO Heavy-Duty Starter Solenoid (SW463)
- ARCO Outboard Starter Motor – Mercury / Force 90–120 HP Sport Jet
Parts Desk Insights
Best suited for Mercury outboard and MerCruiser owners who have already replaced the standard SW058 solenoid and experienced repeat failures, or for high-use applications such as charter boats, commercial vessels, or engines that are started frequently throughout the day. The solid brass stem and high-temp housing address the two most common failure modes of standard solenoids in hot engine compartments. If you’re replacing a solenoid for the first time and your engine sees normal recreational use, the standard SW058 is a cost-effective starting point.
Shipping information
In-stock and OEM parts: ship same or next business day.
Locally warehoused items: ship within 3–4 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.