70 Amp Alternator – Fits MerCruiser V6 & V8 Sterndrive/Inboard Engines (Replaces 862031T1)
70 Amp Alternator – Fits MerCruiser V6 & V8 Sterndrive/Inboard Engines (Replaces 862031T1) is backordered and will ship as soon as it is back in stock.
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Delivery and Shipping
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70 Amp Alternator – Fits MerCruiser V6 & V8 Sterndrive/Inboard Engines (Replaces 862031T1) is backordered and will ship as soon as it is back in stock.
Product Details
This is a direct-replacement 70 Amp Alternator – Fits MerCruiser V6 & V8 Sterndrive/Inboard Engines (Replaces 862031T1). It is specifically designed for General Motors-manufactured MerCruiser V6 and V8 sterndrive and inboard engines from approximately 1999 to 2001, serving as a reliable upgrade or replacement for the original Delco 7SI series unit.
It directly interchanges with Mercury part numbers 862031, 862031T, and 862031T1, along with Delco 19020601 and 19020609, Prestolite 20115019TBA, Arco Marine 20800, and Sierra Marine 18-6293.
- Engineered for marine environments with SAE J1171 certification for ignition protection.
- Features a standard 2.4-inch serpentine belt pulley for compatibility.
- Designed for easy installation using common tools.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Mercury | 862031 |
| Mercury | 862031T |
| Mercury | 862031T1 |
| Delco | 19020601 |
| Delco | 19020609 |
| Daewoo | 219232 |
| Prestolite | 20115019TBA |
| Arco Marine | 20800 |
| Arco Marine | 20815 |
| Sierra Marine | 18-6293 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
This alternator fits a wide range of MerCruiser sterndrive, inboard, and ski applications using GM V6 and V8 blocks.
| Brand | Model | Engine | Years | OEM Part No. |
|---|---|---|---|---|
| MerCruiser | 350 MAG MPI ALPHA & BRAVO | GM 5.7L (350ci) V8 | 1998–2000 | 862031T1 |
| MerCruiser | 350 MAG MPI HORIZON ALPHA & BRAVO | GM 5.7L (350ci) V8 | 1999–2001 | 862031T1 |
| MerCruiser | 4.3L (GEN+) | GM 4.3L (262ci) V6 | 2001–On | 862031T1 |
| MerCruiser | 4.3L EFI | GM 4.3L (262ci) V6 | 1999 | 862031T1 |
| MerCruiser | 4.3L EFI (GEN+) TBI | GM 4.3L (262ci) V6 | 1998–2000 | 862031T1 |
| MerCruiser | 4.3L MPI ALPHA/BRAVO | GM 4.3L (262ci) V6 | 2001–2002 | 862031T1 |
| MerCruiser | 4.3LH (GEN+) (4-BBL) | GM 4.3L (262ci) V6 | 1998–On | 862031T1 |
| MerCruiser | 454 MAG BRAVO MPI (GEN VI) | GM 7.4L (454ci) V8 | 1998–On | 862031T1 |
| MerCruiser | 454 MAG MPI (GEN VI) | GM 7.4L (454ci) V8 | 1998–2000 | 862031T1 |
| MerCruiser | 5.0L (2 BBL.) | GM 5.0L (305ci) V8 | 1998–2002 | 862031T1 |
| MerCruiser | 5.0L EFI (GEN+) | GM 5.0L (305ci) V8 | 1999–2001 | 862031T1 |
| MerCruiser | 5.0L MPI ALPHA/BRAVO | GM 5.0L (305ci) V8 | 1999–2001 | 862031T1 |
| MerCruiser | 5.7L (2 BBL.) | GM 5.7L (350ci) V8 | 1998–2002 | 862031T1 |
| MerCruiser | 5.7L EFI (GEN+) | GM 5.7L (350ci) V8 | 1999–2001 | 862031T1 |
| MerCruiser | 502 MAG MPI (GEN VI) | GM 8.2L (502ci) V8 | 2000–On | 862031T1 |
| MerCruiser | 7.4LX MPI (GEN VI) (L29) | GM 7.4L (454ci) V8 | 1998–2000 | 862031T1 |
| MerCruiser | MX 6.2L MPI | GM 6.2L (377ci) V8 | 1998–On | 862031T1 |
| MerCruiser | MX 6.2L MPI HORIZON | GM 6.2L (377ci) V8 | 2000–2002 | 862031T1 |
| MerCruiser | MX 6.2L MPI HORIZON BRAVO | GM 6.2L (377ci) V8 | 2000–2002 | 862031T1 |
| MerCruiser | 350 MAG MPI HORIZON MIE | GM 5.7L (350ci) V8 | 1999–2001 | 862031T1 |
| MerCruiser | 350 MAG MPI MIE | GM 5.7L (350ci) V8 | 1999–2001 | 862031T1 |
| MerCruiser | 5.7L EFI (GEN+) MIE | GM 5.7L (350ci) V8 | 1999–2001 | 862031T1 |
| MerCruiser | 5.7L MIE | GM 5.7L (350ci) V8 | 1999–2001 | 862031T1 |
| MerCruiser | 7.4L MIE MPI (L29) (GEN VI) | GM 7.4L (454ci) V8 | 1998–2000 | 862031T1 |
| MerCruiser | 8.2L MIE MPI (LH) (GEN VI) | GM 8.2L (502ci) V8 | 2001–On | 862031T1 |
| MerCruiser | MX 6.2L MPI HORIZON MIE | GM 6.2L (377ci) V8 | 2000–2001 | 862031T1 |
| MerCruiser | MX 6.2L MPI MIE | GM 6.2L (377ci) V8 | 2000–2001 | 862031T1 |
| MerCruiser | 350 MAG MPI SKI (GEN+) | GM 5.7L (350ci) V8 | 1998–2001 | 862031T1 |
| MerCruiser | 5.7L COMPETITION SKI (GEN+) | GM 5.7L (350ci) V8 | 1998 | 862031T1 |
| MerCruiser | 5.7L SKI (GEN+) | GM 5.7L (350ci) V8 | 1998–On | 862031T1 |
| MerCruiser | BLACK SCORPION 350 MAG SKI (GEN+) | GM 5.7L (350ci) V8 | 1997–2001 | 862031T1 |
| MerCruiser | BLACK SCORPION MX 6.2L SKI (GEN+) | GM 6.2L (377ci) V8 | 2001–2002 | 862031T1 |
Technical Specs
- Product Type
- Alternator (Delco 7SI Series)
- Output
- 70 Amps
- Voltage
- 12 Volts
- Pulley Type
- Serpentine belt, 2.4" (62mm) diameter
- Regulator Position
- 12:00
- Polarity
- Negative
- Output Stud
- M6-1.0
- Mounting
- M8-1.25 Top Mounting Ear, 8mm Mounting Feet
- Dimensions
- 20.5 × 19.0 × 19.0 cm (8.1 × 7.5 × 7.5 in)
- Weight
- 4.23 kg (9.3 lbs)
- Certification
- SAE J1171 Marine Certified
What’s in the Box
- 1 x Alternator Assembly (862031T1)
Installation Notes
- Disconnect the battery cables (negative first, then positive) to prevent electrical shorts.
- Loosen the serpentine belt tensioner and remove the belt from the alternator pulley.
- Carefully unplug the main wiring harness and disconnect the battery charge wire from the output stud.
- Remove the alternator's mounting bolts and lift the old unit out of the engine bay.
- Compare the new alternator with the old one to ensure the pulley and mounting points align.
- Position the new alternator and loosely thread the mounting bolts.
- Reconnect the wiring harness and charge wire securely.
- Reinstall the serpentine belt, ensuring it is correctly routed on all pulleys. Apply proper tension.
- Tighten all mounting bolts to the manufacturer's specified torque.
- Reconnect the battery cables (positive first, then negative).
- Start the engine and verify the charging system voltage is within the correct range (typically 13.8V-14.7V).
Troubleshooting & FAQ
How do I confirm this alternator fits my specific engine?
The surest way is to match your original part number to one listed in our Part Number Matrix. If you cannot find your part number, please check the Engine & Model Compatibility table. It is critical to confirm the listed engine model, and year range match your setup.
What are the common signs of a failing alternator?
Symptoms include flickering lights, a "Check Battery" or "ALT" warning light on your dash, a weak or dead battery, strange noises from the engine bay (whining or grinding), or a burning rubber smell from the belt slipping on a seized pulley.
Is this a direct, bolt-on replacement?
Yes, this unit is designed to be a direct-fit replacement for the OEM part numbers listed. It uses the same mounting points, pulley type, and electrical connections, requiring no modification for installation on compatible engines.
What is the actual amperage output?
This is a 70 Amp alternator. While some sources may list minor variations, it is rated to perform at 70 Amps, which is the standard for most of the listed MerCruiser applications.
Why does my battery keep dying even with a new alternator?
First, ensure all connections are clean, tight, and free of corrosion. A loose or faulty ground can prevent proper charging. Also, have your battery tested; it may be old and unable to hold a charge. Lastly, check for parasitic drains—electrical components that draw power when the engine is off.
What does SAE J1171 certification mean?
SAE J1171 is a marine safety standard that certifies the component is "ignition protected." This means it is designed to prevent open sparks, making it safe for use in gasoline engine compartments where flammable fuel vapors can be present.
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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