New Lower Unit Gearcase Seal Kit Compatible With 2013-Current Mercury 75 80 90 Hp 4-Cyl Efi 4-Stroke

MERCURY 65-115HP 4-CYL EFI 4-STROKE LOWER UNIT GEARCASE SEAL KIT — Comprehensive Service Kit (2013-Current):

L4NA PLATFORM CONTEXT:
• Mercury L4NA 4-Cylinder 2.1L EFI FourStroke Engine Family
• Per Mercury Marine 90-8M0087844 (2013) Official Documentation
• Covers 65, 75, 80, 90, 100, 115 HP Variants
• Gear Ratio: 2.07:1 (14:29 Tooth Count)
• Includes US Market 75/90/115 HP + EU Market 80/100/115 HP
• Includes SeaPro and Pro XS Variants

MERCURY 4-CYL EFI 4-STROKE LOWER HP APPLICATIONS:
• Mercury 65 HP 4-Cyl EFI 4-Stroke FourStroke (2014 & up — Serial 2B095049 & up)
• Mercury 75 HP 4-Cyl EFI 4-Stroke FourStroke (2013 & up)
• Mercury 75 HP SeaPro 4-Cyl EFI FourStroke
• Mercury 80 HP 4-Cyl EFI 4-Stroke FourStroke (EU Market — 2013 & up)
• Mercury 80 HP JET 4-Cyl EFI FourStroke

MERCURY 4-CYL EFI 4-STROKE MID HP APPLICATIONS:
• Mercury 90 HP 4-Cyl EFI 4-Stroke FourStroke (2013 & up)
• Mercury 90 HP SeaPro 4-Cyl EFI FourStroke
• Mercury 100 HP 4-Cyl EFI 4-Stroke FourStroke (EU Market — 2013 & up)

MERCURY 4-CYL EFI 4-STROKE HIGHER HP APPLICATIONS:
• Mercury 115 HP 4-Cyl EFI 4-Stroke FourStroke (2013 & up)
• Mercury 115 HP SeaPro 4-Cyl EFI FourStroke
• Mercury 115 HP Pro XS 4-Cyl EFI FourStroke 2.1L

⚠️ NOT COMPATIBLE WITH:
• Mercury 2-Stroke Outboards (Different Engine Architecture)
• Mercury 30-60HP Outboards (Different Lower Unit Platform)
• Mercury 135-200HP Verado 4-Cyl Supercharged (Different Platform)
• Mercury 200+ HP Verado 6-Cyl (Different Platform)
• Mercury V6 / V8 4-Stroke Outboards (Different Lower Unit)
• Mercury 150HP FourStroke 3.0L (Different Lower Unit)
• MerCruiser Sterndrive Applications (Inboard/Sterndrive Different)
• Mariner / Yamaha / Honda / Suzuki / Tohatsu Outboards
• Different Gear Ratios (1.75:1 / 2.1:1 / 2.3:1 — Verify 2.07:1)

SPECIFICATIONS:
• Type: Lower Unit Gearcase Seal Kit (Comprehensive)
• Application: Mercury 65-115HP 4-Cyl EFI 4-Stroke FourStroke L4NA
• HP Range: 65 HP through 115 HP
• Engine Type: 4-Stroke EFI
• Cylinder Configuration: 4-Cylinder Inline (L4NA Platform)
• Engine Displacement: 2.1L (Some Earlier Variants 1.85L)
• Gear Ratio: 2.07:1 (14:29 Tooth Count)
• Includes: Multiple Seals, O-Rings, Gaskets, Drain Plug Gasket
• Material: Marine-Grade Rubber Compounds (Saltwater + Heat Resistant)
• Function: Complete Lower Unit Seal Replacement
• Condition: New

OEM PART NUMBERS:
• Mercury: 8M0088080 (Current OEM)
• Mercury: 26-8M0088080 (Alternate OEM Format with 26-Prefix)

KIT CONTENTS:
• Lower Unit Gearcase Seals
• Multiple O-Rings (Various Sizes / Positions)
• Oil Seals (Prop Shaft and Drive Shaft Positions)
• Drain Plug Gasket
• Other Required Gaskets for L4NA Lower Unit

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 L4NA 4-Stroke

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 lower unit from outboard
• Step 3: Take photos and notes of disassembly order / orientation
• Step 4: Disassemble gearcase per Mercury service manual
• Step 5: Remove all old seals, gaskets, o-rings
• 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 lower unit
• Step 12: Reinstall lower unit to outboard
• Step 13: Refill with proper Mercury Hi-Performance Gear Lubricant
• Step 14: Test forward and reverse operation

⚠️ IMPORTANT — VERIFY GEAR RATIO:
• This kit is specifically for 2.07:1 gear ratio Mercury L4NA platform
• Different gear ratios (1.75:1, 2.1:1, 2.3:1) require different seal kits
• Confirm your gear ratio before ordering
• 14 teeth on pinion gear / 29 teeth on driven gear

NOTE: Verify your OEM part number 8M0088080 (or alternate 26-8M0088080) AND your gear ratio (2.07:1) before ordering. ***This kit fits ONLY Mercury L4NA 4-cylinder 2.1L EFI FourStroke 65-115HP outboards.*** Mercury uses different seal kits across HP ranges (Verado 4-cyl, Verado 6-cyl, V6, V8, 3.0L FourStroke 150HP all use different kits), generations, and gear ratio variants. Replace all seals concurrently for proper lower unit longevity.