320472 0391638 0397839 Mercury and OMC Low Pressure Fuel Pump | Genuine Used Part

🔧 Product Description

Genuine OMC Johnson / Evinrude 6HP-15HP Mechanical Fuel Pump - Current Part Number: 0397839

A genuine small-engine diaphragm fuel pump for selected Johnson and Evinrude 6HP to 15HP two-stroke outboards. Current reference 0397839 follows earlier pump 0391638. Number 320472 appears as a cast or production identifier on some pump bodies and should not be presented as a confirmed Mercury service number.

⚙️ Key Features

• Genuine OMC small-outboard fuel pump
• Current service number 0397839
• Earlier service reference 0391638
• Pump-body identifier 320472
• Used primarily on 6HP-15HP Johnson and Evinrude engines

🚤 Compatibility

• Johnson / Evinrude 6HP model families where the 397839 pump is specified
• Johnson / Evinrude 8HP model families
• Johnson / Evinrude 9.9HP and 15HP engines
• Strongly documented 9.9HP / 15HP application range: 1981-1992
• Broader small-engine service-family application: approximately 6HP-15HP
• Fitment is controlled by hose nipples, pulse-port arrangement and mounting pattern

🔌 Function

The pump uses crankcase pulses to move its diaphragm and deliver fuel from the tank to the carburettor through internal one-way valves.

⚠️ Common Signs of Failure

• Engine runs only while primer bulb is squeezed
• Fuel flow falls at high throttle
• Diaphragm leaks or hardens
• Check valves stick
• Pulse passage is blocked
• Pump body or hose nipples crack

🔄 Supersession & Cross Reference

OEM Supersession Chain

• 0397839 is the later documented OMC service reference
• 0391638 is an earlier pump reference
• Related earlier OMC numbers include 0397274, 0395091, 0388685, 0388833, 377927, 386978 and 388681
• 320472 is treated as a casting / production identifier
• Some aftermarket catalogues also list Mercury 0878965 / 878965 for a related small-engine pump configuration; this does not establish a universal genuine Mercury supersession

OEM / Related Numbers

• 0397839 / 397839
• 0391638 / 391638
• 320472
• 0397274 / 397274
• 0395091 / 395091
• 0388685 / 388685
• 0388833 / 388833
• 377927
• 386978
• 388681
• Mercury 0878965 / 878965 - aftermarket catalogue cross-reference only

Aftermarket / Verified Equivalents

• Sierra 18-7350
• Recmar REC1399-07350
• ARCO FP002
• Rareelectrical replacement pump for the 397839 family
• Other marine aftermarket pumps cross-referenced to OMC 0397839

📦 Condition

• Genuine used part
• Removed from running engine where applicable
• In good working condition unless otherwise stated