Marine Starter Motor – Fits Volvo Penta, Mercruiser, OMC 2.5L/3.0L/3.7L/4.3L/V8 (Replaces 50-806965A4, 3862308, 988217)
Marine Starter Motor – Fits Volvo Penta, Mercruiser, OMC 2.5L/3.0L/3.7L/4.3L/V8 (Replaces 50-806965A4, 3862308, 988217) is backordered and will ship as soon as it is back in stock.
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Worry-free returns
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.).
You should expect to receive your refund within four weeks of giving your package to the return shipper, however, in many cases you will receive a refund more quickly. This time period includes the transit time for us to receive your return from the shipper (5 to 10 business days), the time it takes us to process your return once we receive it (3 to 5 business days), and the time it takes your bank to process our refund request (5 to 10 business days).
If you need to return an item, simply login to your account, view the order using the "Complete Orders" link under the My Account menu and click the Return Item(s) button. We'll notify you via e-mail of your refund once we've received and processed the returned item.
Delivery and Shipping
Delivery and Shipping
Free standard shipping on all orders under 1 KG
Marine Starter Motor – Fits Volvo Penta, Mercruiser, OMC 2.5L/3.0L/...
Product Details
This high-torque Marine Starter Motor – Fits Volvo Penta, Mercruiser, OMC 2.5L/3.0L/3.7L/4.3L/V8 is a permanent magnet gear reduction (PMGR) starter designed for reliable performance in harsh marine environments. It provides robust, efficient starting for a wide range of gasoline inboard and sterndrive engines from Mercruiser (up to 1989), OMC (1983–1998), and Volvo Penta (1978–1989), specifically for models using a 12-3/4" flywheel.
This unit is a direct interchange for Mercruiser 50-806963A4, 50-806965A2, 50-806965A4, and 8M0090697; OMC 988217; Volvo Penta 3856003 and 3862308; Sierra 18-5919; and Protorque PH140-0013.
- Installs easily with a direct-fit inline bolt pattern.
- SAE J1171 Marine certified for ignition protection and safe use in gasoline engine compartments.
- Modern PMGR design provides higher torque for reliable starting with less battery drain than original equipment.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Mercruiser | 50-806963A4 |
| Mercruiser | 50-806965A2 |
| Mercruiser | 50-806965A4 |
| Mercruiser | 50-99417A2 |
| Mercruiser | 8M0090697 |
| OMC | 0982121 |
| OMC | 988217 |
| Volvo Penta | 3856003 |
| Volvo Penta | 3862308 |
| Sierra | 18-5919 |
| Protorque | PH140-0013 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
Mercruiser Applications: Fits engines with a 12-3/4" flywheel and serial number 0L096999 or below.
OMC Applications: Fits various Cobra and King Cobra gas sterndrive models from 1983 to 1998.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Mercruiser | 2.5L | 120 | 4-Stroke | Up to 1989 | 50-806965A4 | For engines with 12-3/4" flywheel, S/N 0L096999 and below |
| Mercruiser | 3.0L | 130-140 | 4-Stroke | Up to 1989 | 50-806965A4 | For engines with 12-3/4" flywheel, S/N 0L096999 and below |
| Mercruiser | 3.0LX | 135-140 | 4-Stroke | Up to 1989 | 50-806965A4 | For engines with 12-3/4" flywheel |
| OMC | Cobra 2.5L | 120 | 4-Stroke | 1983–1998 | 988217 | 240 Series |
| OMC | Cobra 3.0L | 130-140 | 4-Stroke | 1983–1998 | 988217 | 240 Series |
| OMC | Cobra 4.3L | 175-205 | 4-Stroke | 1983–1998 | 988217 | 240 Series |
| OMC | Cobra 5.0L | 190-220 | 4-Stroke | 1983–1998 | 988217 | 240 Series |
| OMC | Cobra 5.7L | 235-260 | 4-Stroke | 1983–1998 | 988217 | 240 Series |
Technical Specs
- Product Type
- Permanent Magnet Gear Reduction (PMGR) Starter Motor
- Installation
- Direct replacement, inline bolt pattern
- Fuel Type
- Gasoline
- Connection
- 12V Electrical
- Housing Material
- Die-cast aluminum
- Housing Color
- Silver/metallic
- Dimensions
- 29.5 x 16.5 x 13.0 inches (749.3 x 419.1 x 330.2 mm)
- Weight
- 4.75 kg (10.47 lbs)
- Fitting Type
- Direct bolt-on (inline bolt pattern)
- Thread Size
- 10.1mm ID unthreaded mounting ears
- Working Voltage
- 12V
- Power Rating
- 1.7 kW
- Gear Ratio
- 11-tooth drive gear, 29.6mm (1.165") OD
- Rotation
- Clockwise
- Warranty
- 1-year manufacturer's warranty
- Other Technical Attributes
- SAE J1171 Marine certified for ignition protection; higher torque with less battery drain than original equipment
What’s in the Box
- 1 x Starter Motor Assembly
- 2 x Mounting Bolts (one long, one short)
Installation Notes
- Disconnect the battery terminals (negative first) to prevent electrical shorts.
- Locate and identify the old starter motor on the engine block. Tag or label the electrical wires connected to the starter before removing them.
- Remove the mounting bolts securing the old starter. Support the starter as you remove the last bolt as it can be heavy.
- Compare the new starter with the old one to ensure the mounting pattern and gear are identical. Clean the mounting surface on the engine block.
- Position the new starter, install the mounting bolts, and tighten them to the manufacturer-specified torque. Reconnect the electrical wires to their correct terminals and ensure they are secure.
- Reconnect the battery (positive first) and test the new starter by starting the engine.
Troubleshooting & FAQ
How do I know if this starter fits my engine?
Verify your engine brand, model, and year against the compatibility table. This starter is specifically for gasoline engines with a 12-3/4" flywheel. Always check the part numbers listed in the Part Number Matrix against your old unit or service manual.
What is the advantage of a PMGR starter?
Permanent Magnet Gear Reduction (PMGR) starters are a newer technology compared to older direct-drive starters. They are lighter, more compact, and draw less current from the battery while delivering higher torque for faster, more reliable engine cranking, especially in cold conditions.
My old starter had a different number of teeth. Can I still use this?
No. The number of teeth on the starter's drive gear must match what is required for your engine's flywheel. This model features an 11-tooth drive gear. Using a starter with an incorrect tooth count can cause severe damage to the starter gear and/or the flywheel ring gear.
What are the signs my starter motor is failing?
Common signs include a clicking sound when you turn the key, slow or labored engine cranking, the starter spinning without engaging the engine (freewheeling), or the engine not cranking at all despite having a fully charged battery. Smoke or a grinding noise during startup are also critical indicators of failure.
Is any special maintenance required for this starter?
This starter is a sealed unit and does not require periodic internal maintenance. To ensure longevity, keep all electrical connections clean and tight, and ensure your boat's battery and charging system are in good working order.
The starter just clicks. What's wrong?
A single, loud click usually means the starter solenoid is engaging but the motor isn't turning. This can be caused by a low battery, poor electrical connections (check battery terminals, grounds, and starter connections), or a failed starter motor. Test your battery first, then inspect all cables for corrosion or looseness.
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.
Payment & Security
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