Sierra 18-5960 Alternator, 65 Amp, White, Replaces Mercury Marine 807653T, for MerCruiser 5.7L and 350 Mag GM V-8 Engines

The Sierra 18-5960 is a 65 amp marine alternator built for MerCruiser stern drive applications, supplying reliable charging output to the starting and house battery systems on GM V-8 powered boats. It uses a serpentine pulley and runs on a 12 volt system, matching the charging architecture found on 5.7L and 350 Magnum MerCruiser engines. The alternator is finished in white to match factory engine covers and hardware, and it mounts using a standard engine-mount bracket configuration.

Sierra manufactures the 18-5960 to meet or exceed the performance of the original equipment part it replaces, making it a direct functional match for the Mercury Marine 807653T alternator. It is also cross-referenced to equivalent units from Arco, Mallory, and MES, so boat owners replacing a failed factory or aftermarket alternator can install the 18-5960 without modifying wiring or brackets. The unit ships complete and ready to install in place of the original alternator.

Fitment covers MerCruiser 5.7L EFI MIE GM V-8 engines from 1997, and 350 Magnum EFI and MPI GM V-8 engines from 1997 and up, within the engine serial number ranges noted below.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-5960
• Amp Rating: 65 Amps
• Pulley Type: Serpentine
• Voltage: 12 Volts
• Color: White
• Mounting Type: Engine Mount
• Fuel Type: Gasoline
• Dimensions: 9 inches D x 6 inches W x 6 inches H
• Weight: 12 pounds
• OEM Equivalent Part Number: Mercury Marine 807653T

Fitment

• 5.7L EFI MIE GM V-8, 1997, engine serial number range K040300 to K999999
• 350 Mag. EFI & MPI GM V-8, 1997 & Up, engine serial number range K001501 & Up

Replaces (OEM)

• Mercury Marine 807653T
• Arco 60060
• Mallory 9-19104
• MES 3146M

Frequently Asked Questions

What does the Sierra 18-5960 alternator fit? The Sierra 18-5960 fits MerCruiser 5.7L EFI MIE GM V-8 engines from 1997 (engine serial numbers K040300 to K999999) and 350 Magnum EFI and MPI GM V-8 engines from 1997 and up (engine serial number K001501 and up).

Is the 18-5960 a direct replacement for the Mercury Marine 807653T alternator? Yes, the Sierra 18-5960 is the OEM equivalent of the Mercury Marine 807653T alternator and is designed to meet or exceed the performance of the original part it replaces.

What amp output does this alternator provide? The Sierra 18-5960 is rated at 65 amps, supplying charging current to the battery and electrical system on MerCruiser stern drive engines.

What voltage system is the 18-5960 designed for? This alternator operates on a 12 volt system, matching standard MerCruiser GM V-8 charging systems.

What pulley type does the Sierra 18-5960 use? It uses a serpentine pulley, so the drive belt configuration should match a serpentine belt setup on the engine.

How much does the 18-5960 alternator weigh? The Sierra 18-5960 weighs 12 pounds.

What are the dimensions of this alternator? The Sierra 18-5960 measures 9 inches deep by 6 inches wide by 6 inches high.

Does the 18-5960 cross-reference to other aftermarket brands? Yes, the 18-5960 is interchangeable with Arco 60060, Mallory 9-19104, and MES 3146M in addition to its Mercury Marine 807653T equivalence.

What color is the Sierra 18-5960 alternator? This alternator is finished in white.

How is the 18-5960 mounted to the engine? The Sierra 18-5960 uses a standard engine mount configuration for installation.

Is the Sierra 18-5960 a genuine Sierra part or a generic aftermarket unit? The 18-5960 is manufactured by Sierra as a branded replacement alternator, built to meet or exceed the original equipment part it replaces rather than being an unbranded generic unit.

What is included when ordering the 18-5960? Ordering the Sierra 18-5960 includes one complete 65 amp alternator, ready to install in place of the original unit.