Marine Alternator 12V 65A – Replaces MerCruiser 805447T | SKU 57-60065
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A direct-fit aftermarket replacement alternator for MerCruiser sterndrive and inboard engines requiring the 65-amp output unit. This 12-volt, 65-amp alternator replaces MerCruiser OEM part number 805447T and installs with no wiring modifications — the internal voltage regulator, single groove pulley, and 2-inch mounting foot match the original configuration. The 65A output gives this unit 10 more amps than the standard 55A replacement, making it better suited to vessels with higher house loads from electronics, refrigeration, or live well systems.
Compatible Applications
- MerCruiser 5.0L (305 CID) V8 sterndrive engines equipped with single groove belt drive
- MerCruiser 5.7L (350 CID) V8 sterndrive engines equipped with single groove belt drive
- MerCruiser 7.4L (454 CID) V8 sterndrive engines
- MerCruiser 8.2L (502 CID) V8 sterndrive engines
- MerCruiser inboard engines using the Delco CS-series alternator with single V-belt configuration
- Verify fitment against your engine serial number and parts diagram before ordering — pulley groove count and mounting foot dimensions must match
Replaces
- MerCruiser OEM: 805447T
Product Details
- SKU: 57-60065
- Voltage: 12V
- Output: 65 Amps
- Regulator: Internal voltage regulator
- Pulley: Single groove (included)
- Mounting Foot: 2 inches
- Type: Aftermarket direct replacement
- Condition: New
Related Products
- Marine Alternator 12V 55A – Replaces MerCruiser 817119A1 (57-60050) — lower output option for standard loads
- Quicksilver 70 Amp Alternator – Delco Serpentine – 862031T1 — for serpentine belt systems
- Mercury MerCruiser Quicksilver Serpentine Belt 865615Q04
- Sierra V-Belt 47-15410 – Marine Inboard Sterndrive
- Sierra V-Belt 47-15460 – Marine Inboard Sterndrive
Parts Desk Insights
The 65-amp unit is the better choice over the 55-amp replacement when your vessel is running higher sustained electrical loads — chartplotters, VHF, AIS, live wells, bilge systems, or a 12V refrigeration unit all add up quickly, and the extra 10 amps gives your charging system more headroom, especially at low RPM in no-wake zones or while trolling. Both units share the same mounting configuration, so the decision is purely about output. As with the 55A unit, confirm your belt type before ordering: this is a single groove (V-belt) alternator. If your engine has a multi-groove serpentine belt, the Quicksilver 862031T1 serpentine alternator is the correct choice. Also inspect your drive belt at the time of alternator replacement — a worn or cracked belt on a new alternator is a common cause of premature bearing wear and charging faults.
Shipping information
In-stock and OEM parts: ship same or next business day.
Locally warehoused items: ship within 1-3 business days.
Special-order items: timeline confirmed after order.
Returns & warranty
Returns & Satisfaction Guarantee
We stand firmly behind the quality of every product we sell. Your confidence matters to us — and we back it with a straightforward 30-Day Satisfaction Guarantee.
If you are not fully satisfied, you may request a return within 30 days of delivery. All returns must receive pre-approval prior to being sent back. Unauthorized returns will not be accepted.
To qualify for a return:
Item must be in new, unused condition
Product must be in its original packaging
All parts, components, hardware, manuals, and accessories must be included
Packaging must be undamaged and suitable for resale
Important:
Electronics are strictly inspected. No returns on open-box electronics. Exceptions may apply only with prior written approval. Any electronic unit that has been installed, powered, activated, or altered may not be eligible for return.
We are serious about product integrity — and equally serious about taking care of our customers. If there is ever a product issue, contact us immediately so we can make it right.
For return authorization, please contact our support team before shipping anything back.