Description
Mercury 300L FourStroke (13000002A) — 300 HP V8, 20" Shaft
The Mercury Marine 300L FourStroke (model 13000002A) delivers lightweight big-block performance from a 4.6L V8 with EFI, Smart Start electric starting, and power trim & tilt. This 20" Long (L) shaft configuration uses remote mechanical controls and the heavy-duty 5.44" gearcase with a 1.75:1 ratio, pairing broad torque with excellent prop compatibility.
Why Choose the Mercury 300L FourStroke (13000002A)
- 4.6L V8 muscle: Wide, linear powerband for confident hole shot, strong mid-range, and refined top-end.
- Efficiency tech: Closed-loop EFI and fuel-saving logic to help extend range on long runs.
- Adaptive Speed Control: Holds target RPM through turns, chop, and load changes with fewer throttle corrections.
- High-output charging: 85-amp alternator with Idle Charge helps protect battery voltage when electronics are drawing at idle.
- Heavy-duty gearcase: 5.44" HD case and 1.75:1 gearing for durability and prop flexibility.
- SmartCraft ecosystem: Compatible with SmartCraft gauges/displays for clear data and diagnostics.
- Serviceability: Clean layout, accessible checkpoints, and maintenance reminders to keep you on the water.
Master Specification Table
| Manufacturer | Mercury Marine |
|---|---|
| Model | 300L FourStroke (13000002A) |
| Horsepower | 300 HP |
| Engine Type | V8, 32-valve DOHC FourStroke |
| Displacement | 4.6 L |
| Fuel Induction | Electronic Fuel Injection (EFI) |
| Ignition | SmartCraft-controlled electronic |
| Full-Throttle Operating Range | 5,200–6,000 RPM |
| Charging System | 85 amp alternator with Idle Charge |
| Dry Weight | ≈ 527 lb (lightest configuration) |
| Recommended Fuel | Unleaded 87 Octane (minimum) |
| Oil | Mercury FourStroke oil per climate/service guide |
| Shaft Length | 20" (Long — L) |
| Controls | Remote mechanical throttle & shift |
| Starting | Smart Start Electric |
| Trim & Tilt | Power Trim & Tilt |
| Rotation | Standard |
| Gearcase | 5.44" HD |
| Gear Ratio | 1.75:1 |
| Steering | Remote (hydraulic/other helm systems as rigged) |
| SmartCraft | Fully compatible (gauges & displays available) |
| Emissions | Meets current EPA/CARB requirements |
Operational Details
| Idle & Low-Speed Control | Adaptive Speed Control helps maintain set RPM |
|---|---|
| Fuel Economy Aids | Closed-loop EFI; efficiency-oriented calibration |
| Electrical Budget | 85A supports graphs, pumps, audio, lighting; Idle Charge protects voltage at idle |
| Recommended Prop Strategy | Target upper half of WOT range (5,200–6,000 RPM) under typical load |
| Cooling | Water-cooled with thermostat |
| Exhaust | Through-prop exhaust |
Performance & Setup Notes
- Prop selection: Start with pitch that hits 5,700–6,000 RPM at your usual load/elevation; adjust for seasonal temp/altitude.
- Hull pairings: Performance center consoles, bay/offshore hulls, multi-species deep-V, and heavier pontoons needing strong mid-range.
- Battery planning: Size cranking battery appropriately; follow Mercury cable length/ga guidance to prevent voltage drop.
- Maintenance cadence: Follow Mercury service intervals; log hours and oil changes for warranty recordkeeping.
Boat Fitment & Rigging Checklist
- Confirm model/serial: Verify 13000002A matches build sheet before purchase.
- Transom height: Ensure true 20" transom for L-shaft gearcase immersion.
- Controls & harnesses: Remote mechanical kit, key switch panel, harness lengths per helm location.
- Steering: Hydraulic or compatible helm per manufacturer spec; verify cylinder/ram clearance.
- Fuel system: Clean, ethanol-safe lines and proper venting; use fresh 87-octane minimum.
Get Pricing, Prop, and Rigging Help
Need a turn-key package? We’ll match prop, controls, harnessing, and helm to your boat and fishing/boating style for the Mercury 300L FourStroke (13000002A).
Frequently Asked Questions
Is 13000002A the 20" long-shaft model?
Yes. The 300L designation indicates a 20" (Long) shaft, remote mechanical controls, and electric start.
What gearcase and ratio does this model use?
It features the heavy-duty 5.44" gearcase with a 1.75:1 gear ratio for broad prop compatibility.
How much charging output is available?
The alternator provides up to 85 amps, and Idle Charge helps maintain battery voltage when accessories are drawing at idle.
What is the recommended WOT range?
5,200–6,000 RPM. Prop to the upper half of the range under your typical load and conditions.
What fuel and oil should I use?
Run unleaded 87-octane (minimum) gasoline and Mercury-specified FourStroke oil per your climate and service guide.