Trim Sender/Sending Unit – Fits OMC, Volvo Penta (Replaces 984748, 3850470, 0984731, 0983939)
Trim Sender/Sending Unit – Fits OMC, Volvo Penta (Replaces 984748, 3850470, 0984731, 0983939) is backordered and will ship as soon as it is back in stock.
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Worry-free returns
You may return most new, unopened items within 7 days of delivery for a full refund. We'll also pay the return shipping costs if the return is a result of our error (you received an incorrect or defective item, etc.).
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Delivery and Shipping
Delivery and Shipping
Free standard shipping on all orders under 1 KG
Trim Sender/Sending Unit – Fits OMC, Volvo Penta (Replaces 984748, ...
Product Details
This Trim Sender/Sending Unit – Fits OMC Cobra 1986-1993 (Replaces 984748, 3850470) is designed for OMC Cobra sterndrives from 1986 to 1993 and is also compatible with many Volvo Penta SX and SX-series drives. It provides accurate trim position information to your vessel's gauge.
This unit is a direct replacement for OMC part numbers 984748 and 3850470, Sierra 18-7634, and Volvo Penta 0984731 and 0983939.
- Engineered for a direct bolt-in installation.
- Features a standard 2-wire electrical connection.
- Constructed from a durable aluminum and plastic composite housing.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| OMC | 984748 |
| OMC | 3850470 |
| Sierra | 18-7634 |
| Volvo Penta | 0984731 |
| Volvo Penta | 0983939 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
This unit fits a wide range of OMC Cobra sterndrives manufactured between 1986 and 1993.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. |
|---|---|---|---|---|---|
| OMC | Cobra | 2.3L | 4-Stroke | 1986–1993 | 984748 |
| OMC | Cobra | 2.5L | 4-Stroke | 1986–1993 | 984748 |
| OMC | Cobra | 3.0L | 4-Stroke | 1986–1993 | 984748 |
| OMC | Cobra | 4.3L | 4-Stroke | 1986–1993 | 984748 |
| OMC | Cobra | 5.0L | 4-Stroke | 1986–1993 | 984748 |
| OMC | Cobra | 5.7L | 4-Stroke | 1986–1993 | 984748 |
| OMC | Cobra | 5.8L | 4-Stroke | 1986–1993 | 984748 |
| OMC | Cobra | 7.5L | 4-Stroke | 1986–1993 | 984748 |
It is also compatible with several Volvo Penta SX outdrives. Always verify your specific part number, as year ranges can vary.
| Brand | Model | Years | OEM Part No. |
|---|---|---|---|
| Volvo Penta | SX | Compatible | 0983939 |
| Volvo Penta | SX-S | Compatible | 0984731 |
| Volvo Penta | SX-SLT | Compatible | 0984731 |
Technical Specs
- Product Type
- Trim Sending Unit
- Installation
- Direct bolt-in replacement
- Connection
- 2-wire electrical
- Housing Material
- Aluminum/Plastic Composite
- Dimensions
- ~13.2 cm x 8.9 cm x 5.1 cm (5.2 x 3.5 x 2 inches)
- Weight
- ~0.12 kg (4.23 ounces)
- Wire Length
- ~95 cm (37.4 inches)
- Operating Temperature
- -20°C to 80°C (-4°F to 176°F)
- Warranty
- 1 Year
What’s in the Box
- 1 x Trim Sending Unit (984748/3850470)
Installation Notes
- Disconnect the boat's battery at the main switch or terminal to prevent electrical shorts.
- Locate the old trim sending unit on the sterndrive, typically mounted near the pivot point.
- Carefully unplug the 2-wire electrical connector.
- Remove the screws or bolts securing the old sending unit and set it aside.
- Clean the mounting surface on the sterndrive to ensure a flush fit for the new unit.
- Position the new sending unit, aligning it with the mounting holes, and secure it with the original hardware.
- Reconnect the 2-wire electrical plug firmly.
- Restore power by reconnecting the battery.
- Turn the ignition to the "On" position (without starting the engine) and test the trim gauge by moving the outdrive up and down.
Troubleshooting & FAQ
How do I know if my trim sender is failing?
Common signs of a faulty trim sender include an erratic or non-functional trim gauge on your dashboard, the gauge being stuck at one position, or it showing a position that doesn't match the outdrive's actual angle.
Will this fit my specific Volvo Penta SX drive?
This unit is compatible with many Volvo Penta SX, SX-S, and SX-SLT models. However, the best way to ensure a perfect fit is to match your existing part number to one of the cross-references listed in our Part Number Matrix (0984731, 0983939).
Is any calibration required after installation?
Generally, no complex calibration is needed as it's a direct replacement. After installation, simply check that the gauge reading correctly corresponds to the full up and down positions of the sterndrive. Minor adjustments to the sender's position may be possible on some models if the reading is slightly off.
What are the signs of a failing trim sending unit?
The most common symptoms are an erratic, inaccurate, or completely dead trim gauge on your dashboard. You might see the needle jump around, stay pegged at the top or bottom, or not move at all when you adjust the outdrive trim.
What does the "verify orientation" note on the dimensions mean?
This is a reminder that the physical orientation of the sender during installation is critical. The part may have a specific "up" or "down" direction to ensure the internal mechanism reads the trim angle correctly. Always compare the new part to the old one before installing.
OEM vs. Aftermarket?
This listing is an aftermarket replacement (not OEM). It is built to OEM-level specifications with comparable materials. Manufactured in an ISO 9002 facility, it is batch-inspected for consistency and reliability.
Shipping speed & cost?
We ship worldwide quickly—typical transit is 5–15 days. Standard shipping is free; expedited options will appear at checkout if available for your location.
Warranty & returns?
This product is covered by a 1-year warranty against manufacturing defects under normal use. If you encounter any issues, please contact our support team with your order details. Returns are accepted within our standard window, provided the item is unused and in its original condition. See our full 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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