Mercury Outboard Transom Bracket Screw 500-20 x 4.500 677551
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Mercury 677551 is a genuine OEM transom bracket screw sized .500-20 x 4.500. Current Mercury dealer references show 677551 superseded to 8M0149747, and current OEM parts diagrams place it in the transom bracket assembly as the screw that secures the bracket to the transom.
Key Features
- Genuine Mercury Marine OEM part number 677551.
- Current replacement part number is 8M0149747.
- Size: .500-20 x 4.500.
- Used as the transom bracket to transom screw in current Mercury parts diagrams.
- Current dealer listing shows GTIN 745061169845.
- Current shipping specs are approximately 0.25 lb, 4.78 in. x 1.00 in. x 1.00 in.
Engine Compatibility
This is not a MerCruiser engine part. The strongest supportable fitment for 677551 is Mercury and Mariner outboard transom bracket service. Current Mercury parts references show it in transom bracket diagrams for a wide range of outboards, including 150 HP, 225 HP EFI, 250 HP, 275 HP, and 300 HP applications, along with many other Mercury/Mariner outboard families in dealer where-used records.
Serial Number Fitment Notice
Verify fitment by exact outboard serial number and the correct transom bracket parts diagram before ordering. Because 677551 appears across many Mercury and Mariner outboard families, serial-based confirmation is the safest way to match the correct transom-mount hardware.
When This Part Needs Replacement
Replace this screw when the original is corroded, bent, damaged, stretched, or removed during transom bracket service and no longer suitable for reuse. Since current OEM diagrams place it in the transom bracket mounting stack, correct size and condition matter for secure bracket-to-transom fastening. This is a practical service inference supported by its documented mounting role.
Installation Notes
Install this part only after confirming the correct Mercury or Mariner transom bracket diagram for the outboard being serviced. Current diagrams show it used with related hardware such as washer 28421 and nut 82671117 in the same bracket-to-transom fastening stack.
Alternate/Superseded Part Numbers
Current sources show 8M0149747 as the replacement for 677551.
Parts Desk Insight
With transom bracket hardware, the important match is the exact bracket diagram and screw length. A quick serial-number lookup usually prevents mixing up this 4-1/2 inch screw with the nearby longer transom bracket fasteners in the same assembly.
Shipping: Ships same or next day for fast Canada wide shipping. ⚓
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
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