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Required for fitment review to confirm compatibility.
The OBR replacement lower unit for Mercury 135–150 HP V6 outboards is available in new and remanufactured configurations. The listed standard-rotation gearcases are offered with a 20-inch L or 25-inch XL driveshaft and are intended for selected Mercury V6 two-stroke and 135 DFI applications.
Choose the ME-G6-03A family for a 20-inch L configuration or the ME-G6-04A family for a 25-inch XL configuration. The -N suffix identifies a new gearcase, while -R identifies a remanufactured gearcase.
Horsepower and model year alone cannot confirm fitment. Before ordering, provide the complete engine model and serial number and verify the existing shaft length, gear ratio, and rotation. Counter-rotation, 1.87:1, four-stroke, and Verado applications require a different gearcase.
High-Torque 2:1 Ratio: Perfectly geared for heavier hulls and high-acceleration requirements.
V6 Strength: Built to handle the high-load demands of 135HP and 150HP powerheads.
Superior Protection: Advanced marine-grade finish for maximum corrosion resistance in saltwater.
Current exact-SKU supplier listings identify the following general applications. Every order remains subject to engine serial-number verification.
Current supplier listings show a broad 1979–2014 range, but another available fitment table shows an earlier cutoff. Provide the complete engine model and serial number so the application can be confirmed before fulfillment.
Orders are normally processed within 1–2 business days, Monday through Friday, excluding national holidays. Orders placed after 2:00 p.m., on weekends, or on holidays begin processing on the next business day.
Available shipping methods and charges are displayed during checkout. Delivery estimates depend on the selected service, destination, and carrier conditions. A shipping confirmation email with tracking information is sent after the order has shipped.
Review the shipping address carefully before submitting the order. If an address correction is needed, contact Mariners Warehouse before dispatch. When the shipment arrives, inspect the outer carton and photograph any visible transit damage. Report a lost or damaged shipment promptly to Mariners Warehouse at info@marinerswarehouse.com or 888-812-6287.
| Specification | OBR Replacement Lower Unit for Mercury 135–150 HP V6 | 2.00:1 |
|---|---|
| Manufacturer | OBR Parts & Marine |
| Compatible Engine Make | Mercury |
| Product Family | ME-G6-03A / ME-G6-04A |
| Product Type | Replacement outboard lower unit / gearcase |
| Condition Options | New and remanufactured |
| Engine Family | Selected Mercury V6 two-stroke and 135 DFI applications |
| Horsepower | 135 HP and 150 HP |
| Year Coverage | 1979-2001 |
| Gear Ratio | 2:00:1 |
| Rotation | Standard / right-hand |
| Shaft Options | 20-inch L and 25-inch XL |
| Gearcase Family | 4-3/4-inch hub family |
| New SKUs | ME-G6-03A-N and ME-G6-04A-N |
| Remanufactured SKUs | ME-G6-03A-R and ME-G6-04A-R |
| Model Suffixes | New & Remanufactured |
| Anodes / Zincs | Not included according to the available exact-SKU fitment table |
| Gear Lube | Not included; gearcase ships without oil |
| Warranty | Two-year OBR limited warranty |
| Required Fitment Information | Engine model and serial number, horsepower, model year, shaft length, gear ratio and rotation |
| Major Exclusions | Counter-rotation, 1.87:1, four-stroke, Verado and unverified engine applications |
Choosing the correct Mercury 135–150 HP V6 lower unit starts with five identifiers: the complete engine model and serial number, shaft length, gear ratio, rotation and desired condition. This page covers the OBR ME-G6-03A and ME-G6-04A standard-rotation families.
Choose an ME-G6-03A variant for a 20-inch L shaft or an ME-G6-04A variant for a 25-inch XL shaft. The -N suffix identifies a new gearcase, while -R identifies a remanufactured gearcase. Although current supplier listings identify selected 135–150 HP V6 and 135 DFI applications, horsepower and year alone do not provide a complete fitment match.
Do not use these four variants for a counter-rotation setup, a 1.87:1 application, a four-stroke engine or a Verado. If the existing unit is marked SEI 90-206 or uses a different rotation, compare the alternative product below or request a fitment review. The gearcase ships without oil, so installation must include the correct manufacturer-specified gear lubricant and the applicable OBR break-in procedure.
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The product information made it easy to confirm that this OBR replacement unit matched my Mercury 150 HP V6. The 2.00:1 gear ratio, 20-inch shaft length, and serial-number compatibility guidance were spot on. Always verify your gear ratio before placing an order.
I appreciated that the OBR 135–150 HP V6 page specifically highlighted the 2.00:1 gear ratio requirements. Mariners Warehouse fitment support confirmed my engine year and shaft configuration before shipping, which gave me complete peace of mind.
The unit arrived securely secured in heavy-duty foam packaging. The drive shaft splines and 20-inch shaft lined up perfectly on my 135 HP V6 engine block. Shifts crisp and runs smoothly after completing the recommended break-in hours.
Matching the 2.00:1 gear ratio and engine specs was very easy. The replacement lower unit performs great out on the water, though removing the shipping frame and bracket took a bit of extra time during setup.
Replaced the damaged lower unit on my Mercury 150 HP V6. The listing clearly detailed shaft length parameters and fluid fill steps. After following the proper break-in guidelines, it has performed without a single issue.
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