Mercury MerCruiser — 3/8-16 x 2-3/4 in. Water Pump Screw — 47688
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Mercury MerCruiser Water Pump Screw 47688 | 3/8-16 × 2-3/4 in.
The Mercury MerCruiser 47688 is a genuine OEM 3/8-16 × 2.750 in. hex screw used on select MerCruiser circulating-water-pump and front-cover assemblies. Mercury diagrams identify it as a water-pump-to-cylinder-block fastener, commonly used alongside shorter 32132 mounting screws.
Compatible Applications
- 4.3L / 262 CID V6
- 4.3L Alpha / Bravo
- 350 MAG MPI
- Additional GM-based MerCruiser engines using the specified circulating-water-pump mounting arrangement
Mercury also uses 47688 in some outboard powerhead assemblies, so match it by part number and diagram rather than engine family alone. Confirm your engine serial number and water-pump/front-cover diagram before ordering, since the same assembly can use several different bolt lengths, including 32132 at 1.750 in. and 47688 at 2.750 in.
Part Details
- Part number: 47688
- Full service number: 10-47688
- Brand: Mercury Marine
- Official product type: Water pump mounting screw
- Thread: 3/8-16 UNC
- Length: 2.750 in. / 69.9 mm
- System: Engine cooling / circulating water pump
- GTIN: 745061155220
- Typical quantity: 1 per applicable assembly
Related Parts
- 32132 — 3/8-16 × 1.750 in. water-pump screw
- 34897 — Water pump gasket
- 35342 / 8M0076418 — Water pump stud
- 47277 — Water pump pulley screw
When This Part Needs Replacement
Replace the screw if the threads or hex head are damaged, corrosion is significant, or the fastener cannot be tightened correctly. Inspect all water-pump mounting hardware whenever the circulating pump is removed.
Installation Notes
Install in the original water-pump-to-block position and use the applicable MerCruiser service torque. Check the pump gasket, mating threads, shorter mounting screws, studs, and pulley hardware while the assembly is apart.
Alternate/Superseded Part Numbers
- 47688 — Mercury OEM part number
- 10-47688 — full Mercury service number
- No verified superseding number
Technical FAQ
How is this different from 32132? Both are water-pump mounting screws on the same thread, but 47688 is 2.750 in. long while 32132 is 1.750 in.; they're used at different positions in the same assembly.
Does this fit outboard engines too? Mercury also uses 47688 in some outboard powerhead assemblies. If you are unsure, match by part number and diagram rather than by engine family alone.
Parts Desk Insights
Best use case: This screw is the right fastener when reassembling a MerCruiser circulating water pump or front cover and the original 2.750 in. mounting bolt is damaged or missing.
Common mistake: The most common mistake is confusing this with the shorter 32132 screw used in the same assembly. Matching bolt length and OEM number, not just thread size, avoids installing the wrong screw in the block.
Sizing and fitment: If you are replacing water-pump hardware, check the gasket (34897), studs (35342 / 8M0076418), and pulley screw (47277) at the same time since they're part of the same assembly.
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
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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.
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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.
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