New Lower Unit Gearcase Seal Kit Compatible With 2000 And Newer Mercruiser Alpha One Gen Ii

MERCRUISER ALPHA ONE GENERATION II LOWER UNIT GEARCASE SEAL KIT — Comprehensive Service Kit (1991-Present):

STERNDRIVE PLATFORM CONTEXT:
• Alpha One Generation II is a STERNDRIVE (Drive Unit), NOT an Outboard
• Kit Fits the DRIVE — Not the Engine
• Compatible with Various MerCruiser Engines Paired with This Drive
• Production Run: 1991-Present (Still Active Production)
• Distinct From Alpha One Gen I, MR, R, and Bravo Series Drives

MERCRUISER ALPHA ONE GEN II EARLY PRODUCTION APPLICATIONS:
• MerCruiser Alpha One Gen II Sterndrive (1991-1995)
• Serial Number Range: 0D469859 to 0F679999
• Original Production Era of the Alpha One Gen II Platform

MERCRUISER ALPHA ONE GEN II CONTINUING PRODUCTION APPLICATIONS:
• MerCruiser Alpha One Gen II Sterndrive (1996-Present)
• Continuing Production Through Current Year
• Same Lower Unit Architecture Throughout Production Run

PAIRED ENGINE COMPATIBILITY (Drive Fits — Not Specific to Engine HP):
• MerCruiser 4-Cyl 3.0L (135-181 HP) Paired with Alpha One Gen II
• MerCruiser V6 4.3L (190-225 HP) Paired with Alpha One Gen II
• MerCruiser V8 5.0L (220-260 HP) Paired with Alpha One Gen II
• MerCruiser V8 5.7L (250-310 HP) Paired with Alpha One Gen II
• MerCruiser MAG, EFI, MPI Variants Paired with Alpha One Gen II
• HP Rating of Paired Engine Does NOT Determine Fitment

⚠️ NOT COMPATIBLE WITH:
• MerCruiser Alpha One Generation I (Use 26-33144A2 — Different Drive)
• MerCruiser MR / R Drives (Use 26-33144A2 — Earlier Drive Generation)
• MerCruiser Bravo I (Different Drive — Use Bravo I Specific Kit)
• MerCruiser Bravo II (Different Drive — Use Bravo II Specific Kit)
• MerCruiser Bravo III (Different Drive — Use 26-861695 / 26-861694)
• MerCruiser Bravo X / XR (Different Drive)
• MerCruiser Inboard Applications (Direct Drive — No Sterndrive)
• Mercury Outboard Applications (Different Drive Architecture)
• Volvo Penta / Yamaha / Honda / Suzuki Sterndrives (Different Brands)

SPECIFICATIONS:
• Type: Lower Unit Gearcase Seal Kit (Comprehensive)
• Application: MerCruiser Alpha One Generation II Sterndrive Outdrives
• Drive Type: Sterndrive (NOT Outboard)
• Generation: Gen II (Alpha One Generation 2)
• Year Coverage: 1991-Present
• Includes: Carrier Seal, Impeller Gasket, Seal Ring, Oil Seal, Face Seal, Drain Screw Gasket, O-Ring
• Material: Marine-Grade Rubber Compounds (Saltwater + Heat Resistant)
• Function: Complete Lower Unit Seal Replacement
• Condition: New

OEM PART NUMBERS:
• Mercury/MerCruiser: 26-816575A3 (Current OEM Supersession)
• Mercury/MerCruiser: 26-816575A1 (Older OEM — Superseded)
• Mercury/MerCruiser: 816575A3 / 816575A1 (Without 26- Prefix)

OEM SUPERSESSION CHAIN (Mercury):
• 26-816575A1 → 26-816575A3

KIT CONTENTS:
• Carrier Seal
• Impeller Gasket
• Seal Ring
• Oil Seal
• Face Seal
• Drain Screw Gasket
• O-Ring

WHEN TO USE THIS KIT:
• Lower Unit Complete Rebuild
• Annual Lower Unit Service Interval
• Water in Gear Oil (White / Milky Appearance)
• Gear Oil Leaking from Prop Shaft Area
• Gear Oil Leaking from Drive Shaft Area
• Replacing Forward / Reverse Gear Thrust Bearings
• Replacing Prop Shaft Bearings
• Drive Shaft Service
• Routine Preventive Maintenance for Alpha One Gen II Sterndrive

SYMPTOMS REQUIRING SEAL KIT REPLACEMENT:
• Milky / White Gear Oil at Service Drain (Water Contamination)
• Gear Oil Leaking from Prop Shaft Area
• Gear Oil Leaking from Drive Shaft Area
• Failed Pressure Test During Routine Service
• Lower Unit Running Hot
• Cloudy / Discolored Gear Oil
• Loss of Lubrication
• Routine Annual Service Interval Reached

INSTALLATION:
• Step 1: Drain old gear oil completely (note color / condition)
• Step 2: Remove sterndrive from boat transom assembly
• Step 3: Take photos and notes of disassembly order / orientation
• Step 4: Disassemble lower gearcase per Mercury service manual
• Step 5: Remove all old seals, gaskets, o-rings using proper seal tools
• Step 6: Clean all sealing surfaces thoroughly
• Step 7: Inspect gearcase housing for damage or corrosion
• Step 8: Install new seals with proper orientation (lip direction critical)
• Step 9: Install new gaskets and o-rings with light marine grease
• Step 10: Reassemble gearcase per Mercury service manual torque specs
• Step 11: Pressure test gearcase before reinstalling sterndrive
• Step 12: Reinstall sterndrive to transom assembly
• Step 13: Refill with proper Mercury Hi-Performance Gear Lubricant
• Step 14: Test forward and reverse operation

⚠️ IMPORTANT — VERIFY DRIVE TYPE:
• Look at the drive unit and identify "Alpha One Gen II" stamp / label
• Alpha One Gen II has 4-blade water pump impeller
• Earlier Alpha One Gen I has different design — uses 26-33144A2
• Bravo series drives have different architecture — use Bravo kits
• MR / R drives use 26-33144A2 (earlier generation)

NOTE: Verify your OEM part number 26-816575A3 (or older 26-816575A1) AND your drive type before ordering. ***This kit fits ONLY MerCruiser Alpha One Generation II sterndrive outdrives (1991-Present).*** Alpha One Generation I uses 26-33144A2. Bravo series drives use different kits. ***Note: Alpha One Gen II is a STERNDRIVE — not specific to any engine HP rating. The drive pairs with various MerCruiser engines from 4-cyl to V8.*** Replace all seals concurrently for proper lower unit longevity.