Mercury – 65 Amp Alternator | Delco Serpentine Series | Marine-Grade Construction | 863077T

Overview
There’s a certain comfort that comes from knowing your electrical system is ready for whatever the day throws at you. Whether you’re running the stereo at anchor, trimming the drive as you ease into a slip, or firing up your chartplotter before heading offshore, you expect your alternator to keep everything steady. With this Mercury Marine part, that confidence returns the moment your engine settles into its first smooth idle of the day. It delivers the kind of consistency boaters count on—quiet, steady output that keeps your systems alive without a flicker of doubt.

Key Features

• Exact replacement 65 amp alternator designed for select MerCruiser engines

• Built for serpentine belt applications with a 1.97-inch (50 mm) diameter pulley

• Strong, marine-grade housing engineered to resist heat and moisture

• Produces stable charging power for both engine and onboard electronics

• Direct bolt-on fit designed to replace the original unit with no modification

• Meets all Mercury Marine OEM durability and performance standards

Engine & Boat Compatibility

• Fits the MerCruiser 100 Vazer (2001–2016)

• Fits V6 and V8 MerCruiser sterndrive and inboard engines made by General Motors (serial No. 0M320025–2A528897)

• Fits MerCruiser 496 Magnum and 496 Magnum High Output engines

• Fits MerCruiser 8.1L and 8.1L High Output inboard engines

• Common on cruisers, sport boats, bowriders, performance boats, runabouts, and family day-boats

Performance & Practical Benefits
A dependable alternator is more than a charging component—it’s the heartbeat of your boat’s electrical system. This one delivers a tight, steady output that keeps everything running smoothly, even when you’re powering multiple accessories. You’ll feel the difference in the way your gauges settle, how your electronics respond, and the consistent power delivered to your batteries.

The unit’s marine-built design helps resist corrosion, vibration, and the moisture-rich environment under a hatch. Installation feels natural—mounting points line up, belt alignment stays true, and the serpentine setup allows the alternator to spin with clean efficiency. Once running, the output is impressively stable, giving you confidence whether you’ve been idling through a no-wake zone or pushing hard across afternoon chop. It’s a quiet upgrade, but one that improves every part of the day on the water.

Why Buy OEM
Boaters eventually learn that electrical parts aren’t something to gamble on. An alternator has to handle real marine conditions—heat rising from the block, humidity inside the engine compartment, and vibration that would shake apart an automotive unit. Mercury Marine OEM parts are built for exactly that.

Choosing OEM means:

• Precision fitment matched to your exact engine

• Consistent, reliable power output

• Long service life in harsh marine environments

• Better protection for your batteries and electronics

• No guesswork during installation or operation

It’s the kind of upgrade you make once and do not think about again—and that’s exactly how reliable gear should feel.

FAQ

Q1: Which engines does the Alternator 863077T fit?
It fits the MerCruiser 100 Vazer, select V6 and V8 GM-based MerCruiser engines, 496 Magnum models, and 8.1L High Output inboards.

Q2: How is this different from aftermarket alternators?
This OEM unit is engineered specifically for marine loads, moisture, vibration, and heat, offering stronger long-term reliability.

Q3: How do I confirm it’s the correct replacement?
Match your part number, pulley type (serpentine), and engine serial range with your owner’s manual or service documentation.

Q4: Can it be used in both freshwater and saltwater boats?
Yes—the housing and internal components are designed for harsh marine environments of all kinds.

Q5: Is installation straightforward?
Most boat owners familiar with belt systems will find installation simple with common hand tools.