Aftermarket Tilt/Trim Motor for Mercury/Mariner Outboards – Replaces 828708, 828708T, 878265A4
Aftermarket Tilt/Trim Motor for Mercury/Mariner Outboards – Replaces 828708, 828708T, 878265A4 is backordered and will ship as soon as it is back in stock.
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Aftermarket Tilt/Trim Motor for Mercury/Mariner Outboards – Replace...
Aftermarket Tilt/Trim Motor for Mercury/Mariner Outboards – Replaces 828708, 828708T, 878265A4 is backordered and will ship as soon as it is back in stock.
Product Details
This aftermarket tilt/trim motor is designed to replace the electric motor used in selected Mercury and Mariner power-trim assemblies. It restores powered up-and-down trim operation when the original motor is worn, slow, noisy, or no longer functions.
Reference numbers associated with this motor include Mercury/Mariner 828708, 828708T, 878265A1, 878265A4, and 8M0031551. Aftermarket reference numbers include Sierra 18-6773, Mallory 9-18204, ARCO 6250, and MES T1082M. Reference numbers are provided for comparison only; always confirm the number on your original motor, along with the engine model and serial-number range, before ordering.
- Replacement electric motor for a power-trim or tilt/trim assembly.
- Two-wire DC connection with bullet-style connector ends.
- Reversible rotation for trim-up and trim-down operation.
- Direct bolt-on replacement when the mounting pattern and shaft configuration match the original motor.
Part Number Matrix
The following numbers are manufacturer or aftermarket reference numbers associated with this replacement motor. They should not be treated as proof of universal interchangeability without comparing the original motor and engine application.
| Brand | Reference Number |
|---|---|
| Mercury/Mariner | 828708 |
| Mercury/Mariner | 828708T |
| Mercury/Mariner | 878265A1 |
| Mercury/Mariner | 878265A4 |
| Mercury | 8M0031551 |
| Sierra | 18-6773 |
| Mallory | 9-18204 |
| ARCO | 6250 |
| MES | T1082M |
Documented Application Examples
Catalog records associate the referenced motor numbers with the applications below. These examples are not a complete fitment list. Model, engine configuration, trim system, and serial-number conditions must remain matched when checking compatibility.
| Brand | Model or Application | Horsepower | Stroke | Serial or Application Condition | Associated Reference |
|---|---|---|---|---|---|
| Mercury | 135 Verado, 4-cylinder | 135 HP | 4-Stroke | Serial 1B517159 and newer; also cataloged for serial 0P514869 and newer | 8M0031551 |
| Mercury | 150 Verado, 4-cylinder | 150 HP | 4-Stroke | Serial 1B517159 and newer; also cataloged for serial 0P514869 and newer | 8M0031551 |
| Mercury | 175 Verado, 4-cylinder | 175 HP | 4-Stroke | Serial 1B517159 and newer; also cataloged for serial 0P514869 and newer | 8M0031551 |
| Mercury | 200 Verado, 4-cylinder | 200 HP | 4-Stroke | Serial 1B517159 and newer | 8M0031551 |
| Mercury | XR-6 | 135 HP | Not specified in the catalog record | Serial 0D082000 through 0G303045, or 0G303046 through 0G760299 depending on catalog entry | 878265A4 |
| Mercury | 105 Jet | 105 HP | Not specified in the catalog record | Serial 0D082000 through 0G303045, or 0G303046 through 0G760299 depending on catalog entry | 878265A4 |
Technical Specifications
- Product Type
- Tilt/Trim Motor
- Installation
- Direct replacement when the original motor matches the mounting and shaft configuration
- Connection
- 2-wire DC connection with bullet-style connector ends
- Housing Material
- Metal
- Housing Color
- Black
- Dimensions
- Length: 124.7 mm (4.909 in); outside diameter: 75 mm (2.953 in); shaft diameter: 8 mm (0.315 in)
- Weight
- 1.54 kg (3.39 lb)
- Fitting Type
- Direct bolt-on replacement
- Rotation
- Reversible
- Current Type
- DC
- Shaft Type
- Tanged shaft
What’s in the Box
- 1 x Tilt/Trim Motor
Installation Notes
- Disconnect the boat battery before beginning work.
- Secure the outboard in a safe, fully supported position. Do not rely only on the hydraulic system or a tilt lock if additional mechanical support is required.
- Locate and disconnect the electrical leads from the existing tilt/trim motor.
- Remove the original motor and inspect the mounting surface, shaft interface, seals, and surrounding hydraulic components.
- Compare the replacement motor with the original before installation, including connector style, shaft shape, mounting holes, housing dimensions, and motor orientation.
- Install the replacement motor and tighten the fasteners according to the outboard manufacturer’s service specifications.
- Reconnect the electrical leads and battery. Check that the polarity and wire routing match the original installation.
- Test trim-up and trim-down operation carefully. Stop immediately if the motor runs in the wrong direction, binds, leaks, or makes unusual noise.
Troubleshooting & FAQ
How can I tell whether the tilt/trim motor is failing?
Common symptoms include slow or intermittent movement, clicking or humming without movement, failure in one direction, or complete loss of motor operation. Check the battery, relays, wiring, grounds, and hydraulic assembly before replacing the motor.
Will this fit every Mercury or Mariner engine in the listed horsepower range?
No. Tilt/trim motor fitment can vary by model, engine configuration, trim assembly, and serial-number range. Confirm the original reference number and compare the motor dimensions, shaft, connector, and mounting pattern before ordering.
Are the listed reference numbers OEM numbers?
The Mercury/Mariner numbers are manufacturer reference numbers, while Sierra, Mallory, ARCO, and MES numbers are aftermarket reference numbers. Their appearance in this listing is for identification and cross-reference purposes only.
Is this the complete hydraulic trim assembly?
No. This listing is for the electric tilt/trim motor only. The hydraulic pump, reservoir, ram, relays, wiring, and mounting hardware are not included unless specifically stated in the package contents.
Is the motor reversible?
Yes. It is a reversible DC motor. The boat’s trim switch and relay system normally control direction by reversing polarity.
What maintenance does the motor require?
Keep the housing and electrical connections clean and dry, inspect connectors for corrosion, and check for signs of water or hydraulic-fluid intrusion. Do not disassemble a sealed motor unless instructed by the service procedure for your engine.
Is this an OEM motor?
This is an aftermarket replacement motor, not a Genuine Mercury or Mariner component.
Safety & Important Information
- Verify the original motor reference number, engine model, configuration, and serial-number range before purchase.
- Compare the replacement motor with the original part and product images, including dimensions, connector, shaft, and mounting pattern.
- Disconnect the battery before electrical work and properly support the outboard during installation.
- Professional installation is recommended when working on the outboard’s tilt/trim system.
About Sea Sierra
- Marine Replacement Parts — We provide aftermarket components for repair and maintenance applications.
- Application-Focused Information — Reference numbers and documented model conditions are presented to help customers verify compatibility.
- Practical Replacement Solutions — Each product listing is organized around the component, specifications, and installation considerations.
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