Mercury & Mariner 1988-2006 2-Stroke 100-125 HP 4-Cylinder Outboard Powerhead Parts Diagrams

On this dedicated page, ObParts offers a comprehensive selection of Mercury & Mariner 100–125 HP (1988–2006) 4-cylinder outboard powerhead parts. Whether you’re working on a rebuild or routine maintenance, find essential components such as gaskets, bearings, oil pumps, thermostats, rod bolts, and complete gasket kits. The page also provides detailed parts diagrams to guide accurate part selection and installation. Shop premium OEM and Red Rhino aftermarket parts, like the powerhead gasket kit (OEM #27-13461A99) and various connecting rods, with transparent pricing and “Add to Cart” options for seamless ordering.

The following parts correspond to the numbers on this diagram:

1. Thermostat
• 1988-1993 (143°)
• 1988-2003 (120°)
  

We recommend the following kits for this powerhead:

• Gasket Set
• Carburetor Kit
• Fuel Pump Kit
• In-Line Check Valve
• 90° Check Valve

The diagram to the right is for a Mercury/Mariner Crankshaft Assembly for 4 Cylinder 100-125 HP models from 1988-2006.

The following parts correspond to the numbers on this diagram:

1. Rod Bearing with Cage
2. Wrist Pin Bearings
• 1987-1991 (Bottom guided, Use w/ rod #638-8532-1)
• 1992-2003 (Top guided, Use w/ rod #646-818846)
3. Lower Main Bearing
4. Rod Bolt
5. Upper Main Bearing
6. Connecting Rod
• Bottom Guided
• Top Guided

Although not numbered on the diagram, the following items are available for purchase:

• Crankshaft Seal Kit
• Center Main Bearing