Electric Fuel Pump | Quicksilver 861155A6

Quicksilver 861155A6 OEM Electric Fuel Pump | MerCruiser 4.3L | Carbureted & TBI | Complete Kit with Wiring, Bracket & Fittings

The Quicksilver #861155A6 is the original equipment MerCruiser electric fuel pump for 4.3L MerCruiser carbureted engines and as a delivery pump on select throttle body fuel injected (TBI) models. Complete kit includes the fuel pump, wiring harness, mounting bracket, mounting grommets, and fittings. Replaces multiple superseded MerCruiser part numbers and aftermarket equivalents.

Part Details:

• Part Number: 861155A6 (Quicksilver / OEM MerCruiser)
• SKU: QS-861155A6
• Manufacturer: Quicksilver (OEM Mercury Marine)
• Type: Electric Fuel Pump — Complete Kit
• Application: MerCruiser 4.3L carbureted engines; select TBI models (delivery pump)
• Kit Includes: Fuel pump, wiring harness, mounting bracket, mounting grommets, fittings
• Condition: New

Cross-Reference — Replaces:

• MerCruiser (superseded): 805025A2, 805656A2, 805656A5, 805656A6, 861155A5, 861155A6
• Sierra: 18-8867
• EMP: 1397-00818

Additional Information

OEM Quicksilver — Original Equipment Part:

The 861155A6 is an OEM Quicksilver part — Quicksilver is Mercury Marine's official parts and accessories brand. This is the same fuel pump assembly supplied in original MerCruiser production, not an aftermarket replacement. OEM fitment ensures correct pump pressure specification, electrical connector compatibility, and bracket/mounting geometry for the 4.3L MerCruiser fuel system without modification.

4.3L MerCruiser Application — Carbureted and TBI:

The 861155A6 serves two distinct roles on 4.3L MerCruiser engines depending on fuel system type:

• Carbureted 4.3L models — the primary electric fuel pump, supplying fuel from the tank to the carburetor at the correct pressure and flow rate for carbureted operation
• Throttle body fuel injected (TBI) 4.3L models — used as a delivery (transfer) pump on select TBI configurations, moving fuel from the tank to a higher-pressure in-tank or primary pump for the TBI injection system

Confirm your engine's fuel system type (carbureted vs. TBI) and the role of the electric pump in your specific fuel system configuration before ordering. Cross-reference one of the superseded MerCruiser part numbers against your engine's parts documentation to confirm the 861155A6 is the correct pump for your application.

Superseded Part Numbers — Six MerCruiser Numbers:

Mercury Marine has superseded this pump through multiple part number revisions — 805025A2, 805656A2, 805656A5, 805656A6, and 861155A5 all supersede to the current 861155A6. If your engine's service manual or parts list references any of these earlier numbers, the 861155A6 is the correct current OEM replacement. This consolidation is common in Mercury Marine's parts catalog as assemblies are revised and updated through production runs.

Complete Kit — What’s Included:

The 861155A6 is a complete fuel pump assembly kit, not just the pump element alone. Included components:

• Electric fuel pump — the pump assembly itself
• Wiring harness — pre-wired connector for direct OEM plug-in; no splicing or custom wiring required
• Mounting bracket — OEM bracket for correct pump position and orientation in the engine compartment
• Mounting grommets — vibration-isolating grommets for bracket mounting
• Fittings — fuel line fittings for inlet and outlet connections

All hardware required for a complete OEM pump replacement is included in the kit.

Electric Fuel Pump Failure — Symptoms:

A failing electric fuel pump on the 4.3L MerCruiser typically presents as:

• Engine cranks but does not start — no fuel pressure at the carburetor or TBI unit
• Engine starts but dies at idle or under load — pump supplying insufficient flow for demand
• Rough running, hesitation, or lean stumble under acceleration — pump unable to maintain pressure under load
• No audible pump prime sound when ignition is switched on (key on, engine off) — pump not receiving power or pump motor failed
• Fuel pressure reading below specification with a fuel pressure gauge — test fuel pressure before replacing the pump to confirm the diagnosis

Installation Notes:

• Confirm application (carbureted vs. TBI, pump role) against your engine's parts documentation before ordering
• Cross-reference one of the superseded MerCruiser part numbers (805025A2, 805656A2, 805656A5, 805656A6, 861155A5) if 861155A6 is not listed in older service manuals
• Test fuel pressure before and after installation to confirm diagnosis and verify correct pump operation
• Relieve fuel system pressure before disconnecting fuel lines — follow MerCruiser service manual fuel system safety procedure
• Use OEM fittings included in the kit — do not substitute non-OEM fuel line fittings on a marine fuel system

Frequently Asked Questions

1. Is this an OEM part or an aftermarket replacement?
OEM — the Quicksilver 861155A6 is the original equipment Mercury Marine fuel pump assembly, the same part supplied in MerCruiser production.

2. Does this fit carbureted and fuel injected 4.3L engines?
Yes, for both — as the primary pump on carbureted 4.3L models, and as a delivery pump on select throttle body injected (TBI) 4.3L configurations. Confirm the pump's role in your specific fuel system before ordering.

3. What is included in the kit?
Fuel pump, wiring harness, mounting bracket, mounting grommets, and fittings — everything required for a complete OEM pump replacement.

4. My service manual shows part number 805656A2 — is this the right pump?
Yes — 805025A2, 805656A2, 805656A5, 805656A6, and 861155A5 all supersede to the current 861155A6. The 861155A6 is the correct OEM replacement for any of these earlier numbers.

5. How do I know if my fuel pump has failed?
Test fuel pressure at the carburetor or TBI inlet with a fuel pressure gauge before replacing the pump. Symptoms of pump failure include no-start, dying at idle or load, lean stumble under acceleration, and no audible pump prime when the key is switched on.