Mercury MerCruiser Crankshaft Bearing Cap Screw 843917 / 8M0000463
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Part Details
- Part Number: 843917 (superseded to 8M0000463)
- Brand: Mercury Marine
- Product Type: Crankshaft Bearing Cap Screw (Black Oxide)
- Size: .438-14 x 2.060
- Finish: Black oxide
- GTIN / Barcode: 745061677548
- Superseded By: 8M0000463 — this is the current active Mercury part number
- System: Internal engine assembly — crankshaft / cylinder block
- Diagram Position: Cylinder block / crankshaft bearing cap assembly; also referenced in cylinder head diagrams on applicable engines
Compatible Applications
Verify fitment using your engine serial number before ordering. Confirmed diagram references include:
- Mercury MerCruiser 525 EFI (big-block high-performance)
- Mercury MerCruiser 600 SCi (big-block high-performance)
This fastener appears in internal engine assembly diagrams for Mercury MerCruiser high-performance big-block engines. Serial-number verification is required to confirm the exact location and quantity needed for your engine.
Dimensions & Specifications
- Thread: .438-14 (7/16-14 UNC)
- Length: 2.060 in.
- Finish: Black oxide
- Weight (OEM reference): approx. 0.13 lb (0.059 kg)
- Packed dimensions (OEM reference): approx. 2.50 in. × 0.75 in. × 0.75 in. (6.35 cm × 1.91 cm × 1.91 cm)
When to Replace
Replace this screw when it is damaged, corroded, stretched, or cannot be reliably reused after removal during internal engine service. Crankshaft bearing cap fasteners are torque-critical — inspect carefully and replace any fastener that shows wear or deformation.
Service Interval
Replace as required during engine disassembly or any service procedure that requires removal of the crankshaft bearing caps. Always consult the applicable Mercury MerCruiser service manual for torque specifications.
Installation Notes
Confirm the correct parts diagram for your specific engine serial number before installation. Torque to Mercury MerCruiser specification for crankshaft bearing cap fasteners. Do not reuse fasteners that have been stretched or show signs of corrosion.
Parts Desk Insights
This screw is most commonly needed during full engine rebuilds or bottom-end service on 525 EFI and 600 SCi big-block engines. The most common customer question is whether the old 843917 and current 8M0000463 are interchangeable — they are the same part; 843917 was simply superseded to 8M0000463 in the Mercury parts system. Always order by the current number (8M0000463) and verify quantity required from your specific engine's parts diagram.
Technical FAQ
Q: Is 843917 still available?
A: The original number 843917 has been superseded to 8M0000463, which is the current active Mercury part number for this screw.
Q: How many screws do I need?
A: Quantity varies by engine. Check your engine's crankshaft bearing cap diagram using your serial number.
Q: What torque spec applies?
A: Refer to your Mercury MerCruiser service manual for the torque specification specific to your engine model and serial range.
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.