Piston Rings .010 Oversize Compatible with 1972-1990 Mercury Mariner 35HP-150HP Crossflow 2-Stroke Outboard 2-Cyl 3-Cyl V6 2.885 Bore 39-78816A12 39-88392A12

Piston Ring Set .010 Oversize Compatible with 1972-1990 Mercury Mariner 35HP-150HP Crossflow 2-Stroke Outboard (2.885" Bore)
Direct replacement .010 oversize piston ring set for 1972 through 1990 Mercury and Mariner 35HP through 150HP crossflow 2-stroke outboard motors with 2.875" standard bore. Machined for 2.885" finished bore. Compatible with 3-ring piston configurations. Ring set is for ONE cylinder.

OEM CROSS-REFERENCE PART NUMBERS:
• 39-78816A12 (Standard)
• 39-78811A12 (.015 Oversize)
• 39-88392A12 (.030 Oversize)
• 39-45155A12 (Superseded by 39-78816A12)
• 39-45204A12 (Superseded by 39-78811A12)
• 39-788164A12

SPECIFICATIONS:
• Type: Piston Ring Set (3-Ring Configuration) • Oversize: .010 Over • Standard Bore: 2.875" • Finished Bore: 2.885" • Engine Type: 2-Stroke Crossflow Outboard
• Horsepower Range: 35HP-150HP
• Cylinder Configurations: Inline 2-Cyl, Inline 3-Cyl, V6 6-Cyl
• Ring Quantity: Per Cylinder

APPLICATIONS — 2-CYLINDER MODELS:
• 35HP 2-Cyl Crossflow (1984-1989)
• 40HP 2-Cyl Crossflow (1972-1983)

APPLICATIONS — 3-CYLINDER MODELS:
• 50HP 3-Cyl Crossflow (1984-1990)
• 60HP 3-Cyl Crossflow (1984-1990)
• 65HP 3-Cyl Crossflow (1973-1976)
• 70HP 3-Cyl Crossflow (1977-1983)

APPLICATIONS — 6-CYLINDER MODELS:
• 115HP V6 Crossflow (1984-1988)
• 140HP V6 Crossflow (1978-1981)
• 150HP V6 Crossflow (1973-1978)

⚠️ Verify OEM part number and 3-ring piston configuration from your original engine before ordering.