Why pay dealer markup? Get genuine Mercury Marine quality at discount pricing. This HOSE ASSEMBLY, Circulation Pump to Thermostat Housing delivers OEM reliability with savings up to 20% below retail.

Manufactured to strict Mercury Marine quality standards, this pump ensures reliable operation across all engine RPM ranges. Part number 861590A05 is manufactured to exact Mercury Marine factory specifications for precision installation and optimal performance. Constructed from premium marine-grade materials designed to withstand harsh saltwater and freshwater environments.

Why risk your Mercury engine with questionable aftermarket parts? Genuine part 861590A05 is built to last, backed by Mercury Marine’s decades of marine engineering expertise and proven reliability.

Compatible Mercury Marine Engines

FITS: 4-383HP MERCRUISER, RACE STERNDRIVE

• Fits MERCRUISER, RACE STERNDRIVE 4-383HP engines
• Compatible HP: 4HP, 5HP, 357HP, 383HP
• Covers 24 serial number ranges
• Configurations: Outboard, Sterndrive
• OEM genuine Mercury Marine part

COMPLETE SERIAL NUMBER COMPATIBILITY:

4HP Models

• 4HP OUTBOARD (Mercruiser): 0M615000-0W300012, 0W300013-0W309999, 0W310000-0W649999, 0W650000-1A063239

5HP Models

• 5HP OUTBOARD (Mercruiser): 0M317000-0W090899, 0W090900-0W689999

357HP Models

• 357HP OUTBOARD (Mercruiser)

383HP Models

• 383HP OUTBOARD (Mercruiser)
• 383HP STROKER (Mercruiser)

HP Models

• HP OUTBOARD (Mercruiser): 0M391600-0W689999, 0W690000-0W698432, 0K040001-0M391599, 0M391750-0W689999, 0W690000-0W698432, 0L670015-0M391599, 0L680003-0M299999
• HP STERNDRIVE (Race Sterndrive): 0K000656-0L600314

Looking for your Mercury engine serial number? Our helpful guide shows you exactly where serial numbers are located on different engines.

Verification & Support

Verify part 861590A05 works with your Mercury using our parts finder tool. Have questions? Reach out using the contact buttons at the bottom of this page — our team is here to help by text, call, or email

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