Description
Marine Electric Choke Assembly for Mercruiser 2-Barrel Mercarb
The iFJF 18-7665 marine electric choke assembly is a direct replacement for Mercruiser 2-barrel Mercarb carburetors on 3.0L 4-cylinder sterndrive engines. This choke automatically enriches the fuel mixture during cold starts using a 12V electric heating element — eliminating the need for manual choke cables or operator intervention. Replaces OEM 70125A-1 and Sierra Marine 18-7665.
Key Features
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Automatic Electric Operation: 12V heating element progressively opens the choke plate as the engine warms up — no cables, no manual adjustment.
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Direct OEM Replacement: Precision-fit for Mercruiser 2-barrel Mercarb carburetors. Replaces OEM 70125A-1 and Sierra 18-7665.
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Improved Cold Starts: Provides the correct cold-start fuel enrichment for instant starting and smooth warm-up, even after extended storage.
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Corrosion-Resistant Construction: Designed for the harsh marine engine compartment environment — resists salt air corrosion and humidity damage.
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Plug-and-Play Installation: Connects to the existing 12V ignition-switched power source. Uses the same mounting pattern as the original choke.
Compatibility
| Engine |
Carburetor |
Application |
| Mercruiser 3.0L (181 ci) |
2-Barrel Mercarb |
Sterndrive, 4-cylinder, various years |
| Mercruiser 3.0LX |
2-Barrel Mercarb |
Sterndrive, 4-cylinder |
| Mercruiser 3.0L MPI (Verify) |
N/A — Fuel Injected |
❌ Not Compatible — MPI models don't use carburetors |
Cross-Reference
| Brand |
Part Number |
| Sierra Marine |
18-7665 |
| Mercruiser OEM |
70125A-1 |
Signs of a Failing Electric Choke
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Hard cold starting: Choke doesn't close fully — engine cranks excessively before firing.
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Engine stalls when cold: Choke opens too quickly, leaning out the mixture before the engine is warm.
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Black smoke / rich running when warm: Choke stays partially closed — heating element has failed.
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Rough idle after cold start: Choke opening inconsistently due to intermittent electrical connection.
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High idle persists too long: Heating element weak — choke takes excessive time to fully open.
Installation Overview
- Disconnect battery negative terminal (safety first in marine environments).
- Remove the flame arrestor / air cleaner assembly.
- Disconnect the old choke electrical connector.
- Remove the old choke assembly (typically 2-3 screws on the carburetor housing).
- Install the new iFJF 18-7665 choke, ensuring the choke plate linkage engages correctly.
- Connect the electrical lead to 12V ignition-switched power.
- Verify choke operation: cold engine → choke plate should be nearly closed. Apply 12V → plate should slowly open over 2-5 minutes.
Frequently Asked Questions
Q: Does this fit all Mercruiser 3.0L engines?
A: This choke fits Mercruiser 3.0L engines with the 2-barrel Mercarb carburetor. It does NOT fit 3.0L MPI (multi-port fuel injection) models, which don't use a carburetor or choke. Verify your engine has a carburetor before ordering.
Q: How do I test my existing choke?
A: With a cold engine, remove the flame arrestor. The choke plate should be nearly closed. Start the engine and observe — the plate should slowly open over 2-5 minutes. If it stays closed after 5+ minutes, the heating element is dead. If it snaps open immediately, the bimetal spring is broken.
Q: Does this require 12V constant or switched power?
A: Connect to ignition-switched 12V (only powered when the key is ON). Connecting to constant 12V will keep the choke heating element energized and drain your battery.
Q: Can I adjust the choke opening speed?
A: The opening speed is determined by the heating element and bimetal spring — not user-adjustable. However, you can adjust the initial choke plate gap via the choke housing rotation. Mark the original position before removal.
Q: Is the gasket included?
A: If the kit includes a mounting gasket, it will be in the package. If your original gasket is in good condition, it can be reused.
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