Mercury & Mariner 1998-2005 2.5L 135-175 HP DFI Outboard Powerhead Parts Diagrams

This page offers parts diagrams and listings specifically for the Mercury & Mariner 2.5L V6 135-175 HP DFI (1998–2005) outboard powerhead. Browse through comprehensive exploded views and step-by-step component breakdowns, featuring everything from crankshaft assemblies and connecting rods to gasket and o-ring kits. Available parts include crankshaft seal kits, rod bearings, wrist pin bearings (distinct options for 1998-2000 and 2001-on), center/upper/lower main bearings, rod bolts, thermostat, and more. Whether you're repairing or rebuilding, OBParts simplifies the process by offering easy-to-navigate diagrams and OEM or aftermarket components—all in one place.

The diagram to the right is for a Mercury & Mariner Powerhead for V6 135-175 HP 2.5L DFI models from 1998-2005. The following parts correspond to the numbers on this diagram:

1. Thermostat
2. Cylinder Head O-Ring Kit (not pictured)

We recommend the following kits for this powerhead:

• Fuel Pump Kit
• Gasket Set

The diagram to the right is for a Mercury & Mariner Crankshaft Assembly for V6 135-175 HP 2.5L DFI models from 1998-2005. The following parts correspond to the numbers on this diagram:

1. Rod Bearing
2. Wrist Pin Bearings
• 1998-2000
• 2001 & up
3. Center Main Bearing
4. Upper Main Bearing
5. Lower Main Bearing
6. Rod Bolt
7. Connecting Rod
• 1998-2000
• 2001 & up

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

• Crankshaft Seal Kit