ARCO Starter Mounting Bolt Kit – Gear Reduction Starters | SKU 57-MBK450
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ARCO Starter Mounting Bolt Kit – Gear Reduction Starters
A purpose-built mounting bolt kit for installing gear reduction starters on marine inboard and stern-drive engines. This kit includes two long 3/8–16 N.C. thread mounting bolts and is the correct hardware to use when upgrading from a 10MT-style starter to a gear reduction unit. Using the right mounting hardware ensures a secure, properly aligned installation that protects both the starter and the engine block.
Features
- Includes 2 long mounting bolts, 3/8–16 N.C. thread
- Required when replacing a 10MT starter with a gear reduction starter
- Fits ARCO gear reduction starters with staggered bolt mounting pattern
- Also fits all Delco gear reduction starters with staggered bolt mounting pattern
- Not compatible with metric engines or 10MT starters
Compatible Applications
- ARCO gear reduction starters (staggered bolt mounting pattern)
- Delco gear reduction starters (staggered bolt mounting pattern)
- Inboard and stern-drive engines using 3/8–16 N.C. thread starter mounting
- Not compatible: metric engines or 10MT-style starters
Pairs Well With
- ARCO Starter Solenoid – MerCruiser, Cobra & Volvo Penta (SW450)
- ARCO Heavy-Duty Starter Solenoid – MerCruiser, OMC, Volvo Penta (SW463)
Parts Desk Insights
Best suited for anyone upgrading an older 10MT-style starter to a modern gear reduction unit. Gear reduction starters use a different bolt spacing and length than 10MT starters, so the factory bolts from the old unit will not work. This kit is the correct hardware to complete that swap cleanly. Confirm your engine uses standard N.C. (National Coarse) thread — metric-threaded engine blocks require different hardware not included in this kit.
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.