Speedometer Connector Adaptor – Fits MerCruiser Bravo I, II, III Stern Drives (Replaces 815303T, 12899)
Speedometer Connector Adaptor – Fits MerCruiser Bravo I, II, III Stern Drives (Replaces 815303T, 12899) is backordered and will ship as soon as it is back in stock.
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Delivery and Shipping
Delivery and Shipping
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Speedometer Connector Adaptor – Fits MerCruiser Bravo I, II, III Stern Drives (Replaces 815303T, 12899) is backordered and will ship as soon as it is back in stock.
Product Details
This Speedometer Connector Adaptor is designed for MerCruiser Bravo series stern drives, including Bravo I, II, and III models. It serves as the required adaptor for a proper connection of the speedometer tubing at the bell housing, ensuring accurate speed readings.
It is a direct replacement for Mercury/MerCruiser part numbers 815303T and 12899.
- Installs at the bell housing.
- Connects the speedometer pickup tube.
- Made from durable plastic to withstand the marine environment.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Mercury/MerCruiser | 815303T |
| Mercury/MerCruiser | 12899 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
| Brand | Model | Rated HP | Stroke | OEM Part No. |
|---|---|---|---|---|
| MerCruiser | Bravo I | Various | 4-Stroke | 815303T/12899 |
| MerCruiser | Bravo II | Various | 4-Stroke | 815303T/12899 |
| MerCruiser | Bravo III | Various | 4-Stroke | 815303T/12899 |
Technical Specs
- Product Type
- Speedometer Connector Adaptor
- Installation
- Bell Housing
- Connection
- Speedometer Tubing
- Housing Material
- Plastic
- Dimensions
- 9.5 x 10.2 x 1.5 cm
- Weight
- 0.01 kg (0.022 lb)
- Fitting Type
- Speedometer Pickup Tube Connection
- Other Technical Attributes
- Connects speedometer tubing at the bell housing of Bravo I, II, III stern drives
What’s in the Box
- 1 x Adaptor (815303T/12899)
Installation Notes
Installation involves locating the existing speedometer connection at the bell housing, carefully disconnecting the speedometer tube, and removing the old adaptor. Clean the fitting area before securely attaching the new adaptor, ensuring a tight connection for the speedometer tubing to prevent leaks and ensure accurate readings.
Troubleshooting & FAQ
What models does this adaptor fit?
This adaptor is specifically designed for MerCruiser Bravo series stern drives, including Bravo I, Bravo II, and Bravo III models.
Where is this adaptor installed?
It is installed at the bell housing of the stern drive, where it connects the speedometer pickup tubing to the drive unit.
What are the signs of a failing speedometer adaptor?
A common symptom is an erratic or completely non-functional speedometer. This is often caused by a cracked or leaking adaptor that prevents water pressure from reaching the gauge correctly.
Is this a direct replacement for my OEM part?
Yes, it serves as a direct, aftermarket replacement for Mercury/MerCruiser part numbers 815303T and 12899.
How do I know if my speedometer issue is from the adaptor or the gauge?
First, visually inspect the adaptor and tubing for cracks or loose connections. If no damage is visible, you can disconnect the tube at the transom and use a low-pressure air source to see if the gauge needle moves. If it moves, the issue is likely with the adaptor or pickup tube in the drive; if not, the problem may be the gauge or the tubing itself.
OEM vs. Aftermarket?
This listing is an aftermarket replacement (not OEM). Built to OEM-level specifications with comparable materials. Manufactured in an ISO 9002 facility, batch-inspected for consistency.
Shipping speed & cost
We ship worldwide quickly—typical transit 5–15 days. Standard shipping is free; expedited options appear at checkout where available.
Warranty & returns
Covered by a 1-year warranty against manufacturing defects under normal use. If issues arise, contact support with your order details. Returns are accepted within our standard window (unused & in original condition). See our policy page or reach out for instructions.
Safety & Important Info
- Verify images/specifications vs your original part. If anything differs—even if your model appears compatible—do not purchase.
- This is an aftermarket replacement, not an OEM component.
- Professional installation is recommended for safety and performance.
About Sea Sierra
- Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and tested for real-world conditions.
- Fast Global Fulfillment — Free standard delivery to most regions in 5–15 days.
- Manufacturer-Direct Value — Fair pricing without compromising on materials or QC.
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