O - Ring Cylinder Head - Mercury / Mariner 200-300 HP (2000-2001, 2004) OEM# 25-818573 | WSM 505-51

O-Ring Cylinder Head Mercury / Mariner 200 - 300 Hp OEM# 25-818573

This WSM o-ring cylinder head is a quality aftermarket replacement part designed for Mariner 6 Cyl 3.625 Bore 3L 225 and 8 other compatible models.

It replaces selected OEM reference numbers including 25-818573 and is suitable for service, repair and rebuild work.

Key Features

• Quality aftermarket replacement part from WSM
• Engineered for dependable fit, function and service life
• Designed for marine and powersports repair and maintenance
• Compatible with 9 listed fitments
• Replaces selected OEM reference numbers listed below

Product Details

• Brand: WSM
• WSM Part Number: 505-51
• Product: O-Ring Cylinder Head
• OEM Reference: 25-818573
• Application: Mariner 6 Cyl 3.625 Bore 3L 225 and 8 other compatible models

Product Fitment

This part is suitable for the following models:

• Mariner 6 Cyl 3.625 Bore 3L 225 – All Years
• Mercury 6 Cyl 3.625 Bore 3L EFI 225 – 1994-2001
• Mercury 6 Cyl 3.625 Bore 3L EFI 250 – 1995-2001
• Mercury 6 Cyl 3.625 Bore 3L Pro Max 300 – 1995-2001
• Mercury 6 Cyl 3.625 Bore 3L XB 250 – 1998-2000
• Mercury 6 Cyl 3.6265 Bore 3L Optimax 200 – 2000-2004
• Mercury 6 Cyl 3.6265 Bore 3L Optimax 225 – 1997-2000
• Mercury 6 Cyl 3L Carb Sea Pro 225 – 1998-2001
• Mercury – 1995-2001

Why Buy WSM

WSM is a trusted manufacturer of aftermarket marine and powersports parts, known for dependable quality, strong fitment coverage and workshop-ready replacement components.

You May Also Need

Browse related parts for compatible models:

• Seal Carrier Assembly Mercury / Mariner / Mercruiser 200 - 300 Hp OEM# 18-2354 – 449-332
• Gasket Reed Block Mercury / Mariner 200 - 300 Hp 6 Cyl 3L 95-05 OEM# 27-8141951 – 516-40
• Tilt Tube Stainless Steel Mercury / Mariner / Force 65 - 300 Hp OEM# 826125A1 – 986-165
• O-Ring Cylinder Head Mercury / Mariner 200 - 300 Hp 3L / 3.2L OEM# 25-818574 – 505-50

Please use the fitment guide, OEM references and images to confirm this is the correct part before ordering.