Upper Main Bearing Compatible With 1985-2014 Mercury Mariner Looper Optimax 65 70 75 80 90 100 115

PART NUMBERS:
• 31-43013A1 / 3143013A1
• 31-43013T1 / 3143013T1
• 31-43013T3 / 3143013T3 (supersedes A1 and T1)

SPECIFICATIONS:
• Component: Upper Main Bearing
• Engine: 3-Cyl / 4-Cyl 2-Stroke Looper + 1.5L Optimax
• Horsepower: 65-125 HP
• Brand: Mercury / Mariner

APPLICATIONS:
• 3-Cyl Looper 3.375/3.500 Bore: 65/70/75/80/90 HP (1987-2006)
• 4-Cyl Looper 3.375/3.500 Bore: 80/100/115/125 HP (1985-2006)
• 1.5L Optimax 3.6255 Bore: 75/90 HP (2010-2014)
• Applicable Mariner models by part number

PRODUCT DETAILS:
This upper main bearing fits Mercury and Mariner 2-stroke outboard motors spanning 3-cylinder and 4-cylinder Looper configurations from 65 through 125 HP, plus the 1.5L Optimax 75 and 90 HP models, produced between 1985 and 2014. The Mercury Looper engine design was the primary 2-stroke platform for nearly 20 years, covering both 3.375 bore and 3.500 bore variants in 3-cylinder and 4-cylinder configurations. Also compatible with the later 1.5L Optimax 3-cylinder direct injection engines in 75 HP and 90 HP, demonstrating the wide application range of this bearing across Mercury's mid-range outboard lineup. The upper main bearing supports the crankshaft at the top of the powerhead and must handle radial loads from crankshaft rotation during engine operation. A worn upper main bearing causes increased engine noise, crankshaft misalignment, and power loss. Manufactured to specifications for proper fit in Mercury and Mariner outboard applications. Verify your part number before ordering to confirm correct application.

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