Sierra 18-6293 Marine Alternator, 12V 70A, Fits MerCruiser 454 Mag. MPI, 454 Mag. MPI MIE and 502 Mag. MPI GM V-8 (1998 and Up)

The Sierra 18-6293 is a 12-volt, 70-amp marine alternator built to keep a stern drive's battery and electrical system properly charged under continuous marine duty. It is constructed with heavy-duty bearings and a heavy-duty regulator for extended service life, along with a high-quality stator and heavy-duty rectifiers to maintain charging efficiency even at high engine hours. Every unit is 100% load tested before it leaves the factory, so it is verified to perform correctly out of the box rather than relying on spot checks. The alternator meets or exceeds USCG, SAE J1171, and ISO 8846 marine safety standards, which govern spark and ignition protection aboard boats, so it is built specifically for the marine environment rather than adapted from an automotive part.

Electrically it is a 12V, 70A unit with an internal fan, an M8-1.25 mounting stud, and a 6-groove, 2.44 inch diameter serpentine pulley. It uses a hinge mount configuration (7-SI style) with 8mm unthreaded mounting holes, and has a machined exterior finish. The 18-6293 is designed for MerCruiser 454 Mag. MPI, 454 Mag. MPI MIE, and 502 Mag. MPI GM V-8 engines from serial number 1998 and up, and it directly replaces several common Mercury Marine, Delco, Arco, API Marine, and Daewoo alternator part numbers, making it a straightforward drop-in charging system upgrade or replacement.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-6293
• Voltage: 12V
• Amperage: 70A
• Fan Type: Internal
• Stud Size: M8-1.25
• Pulley Type: 6-Groove, 2.44 inch Diameter Serpentine Pulley
• Mounting Type: Hinge Mount, 7-SI
• Mounting Holes: 8mm Unthreaded
• Weight: 9.5 pounds
• Product Dimensions: 7.5 x 7.5 x 7.5 inches
• Finish: Machined
• UPC: 808282187378

Fitment

• MerCruiser 454 Mag. MPI GM V-8, 1998 and up (serial number L010029 and up)
• MerCruiser 454 Mag. MPI MIE GM V-8, 1998 and up (serial number L002200 and up)
• MerCruiser 502 Mag. MPI GM V-8, 1998 and up (serial number L017000 and up)

Replaces (OEM)

• Mercury Marine 862031T, 862031, 862031T1
• API Marine 20099
• Arco 20800
• Daewoo 219232
• Delco 19020601, 19020609

Frequently Asked Questions

What does the Sierra 18-6293 alternator replace? The 18-6293 directly replaces Mercury Marine 862031T, 862031, and 862031T1, as well as API Marine 20099, Arco 20800, Daewoo 219232, and Delco 19020601 and 19020609.

Is the 18-6293 a 12 volt or 24 volt alternator? It is a 12-volt, 70-amp alternator, sized for standard 12V stern drive charging systems.

What engines does the Sierra 18-6293 fit? This alternator fits MerCruiser 454 Mag. MPI (serial number L010029 and up), 454 Mag. MPI MIE (serial number L002200 and up), and 502 Mag. MPI (serial number L017000 and up) GM V-8 engines, all from 1998 and up.

What size is the mounting stud on this alternator? The 18-6293 uses an M8-1.25 mounting stud.

What pulley does the 18-6293 use? A 6-groove serpentine pulley with a 2.44 inch diameter is fitted to this alternator.

Is the alternator internally or externally fanned? The Sierra 18-6293 has an internal fan design, matching the 7-SI style hinge mount configuration it uses.

How much does the 18-6293 alternator weigh and what are its dimensions? It weighs 9.5 pounds and measures approximately 7.5 x 7.5 x 7.5 inches.

Does the 18-6293 come tested before shipping? Yes, every 18-6293 alternator is 100% load tested at the factory for assured reliability out of the box.

What size are the mounting holes? The 18-6293 has 8mm unthreaded mounting holes as part of its hinge mount design.

Is the Sierra 18-6293 genuine OEM or an aftermarket part? It is a Sierra-manufactured marine alternator engineered to meet or exceed the performance of the original equipment part it replaces, including USCG, SAE J1171, and ISO 8846 standards.

Can the 18-6293 be used on both 454 Mag. MPI and 502 Mag. MPI engines? Yes, the same 18-6293 alternator is listed for MerCruiser 454 Mag. MPI, 454 Mag. MPI MIE, and 502 Mag. MPI GM V-8 engines from 1998 and up.

What finish does the 18-6293 alternator have? It has a machined exterior finish.