PART NUMBERS:
• 31-812873A1 31812873A1
ITEM SPECIFICATIONS:
• Component: Upper Main Bearing
• Engine: 3-Cylinder 2.955 Bore Looper
• Horsepower: 45/50/55/60 HP
• Brand: Mercury / Mariner
COMPATIBLE MODELS:
• 50 HP Looper 3-Cyl (1991-1997)
• 60 HP Looper 3-Cyl (1991-1997)
• Jet 45 HP 3-Cyl (1991-1997)
• Sea Pro 55 HP 13-Spline (1995-1997)
• Applicable Mariner models by part number
PRODUCT DETAILS:
Direct replacement upper main bearing for Mercury and Mariner 3-cylinder Looper outboard engines covering 50 HP, 60 HP, Jet 45 HP, and Sea Pro 55 HP models produced between 1991 and 1997. The Looper designation identifies Mercury's loop-charged 2-stroke engine design that was the standard configuration for their mid-range outboard motors during this era. All four horsepower ratings in this family share the same 3-cylinder block with 2.955 inch bore, and the upper main bearing is common across the standard, jet drive, and Sea Pro commercial variants. The upper main bearing supports the crankshaft at the top of the powerhead assembly, and proper bearing condition is essential for maintaining crankshaft alignment and engine reliability. A failing upper main bearing typically presents as increased engine noise, vibration at certain RPM ranges, reduced power output, or visible crankshaft play during engine disassembly. Manufactured to match specifications for reliable performance in Mercury and Mariner outboard powerhead applications. Always confirm your model and part number before purchasing to verify proper fitment for your Mercury or Mariner outboard motor.
PRODUCT NOTICE:
As a parts distributor we mostly sell aftermarket parts (any OEM parts would be noted as such). Aftermarket parts are not sourced from the original vehicle or equipment manufacturer, but are designed to function the same as - if not better than - the original. All parts sold are new.
WARNING - This product may expose you to chemicals which are known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov
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