Idle Air Control (IAC) Motor for Volvo Penta Marine Engines — Replaces Volvo Penta 3843751 / Sierra 18-7705
Idle Air Control (IAC) Motor for Volvo Penta Marine Engines — Replaces Volvo Penta 3843751 / Sierra 18-7705 is backordered and will ship as soon as it is back in stock.
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Idle Air Control (IAC) Motor for Volvo Penta Marine Engines — Repla...
Idle Air Control (IAC) Motor for Volvo Penta Marine Engines — Replaces Volvo Penta 3843751 / Sierra 18-7705 is backordered and will ship as soon as it is back in stock.
Product Details
This Idle Air Control (IAC) Motor is an aftermarket replacement for the Volvo Penta idle air control motor identified by OEM part number 3843751. The IAC motor is used in an electronic fuel-injection system to help regulate bypass air and maintain stable engine idle speed.
The Sierra catalog identifies aftermarket part number 18-7705 as an IAC motor that replaces Volvo Penta 3843751. Because marine engine applications can vary by model, production year, throttle-body configuration, and serial number, confirm the number on your original component and the connector and mounting arrangement before ordering.
- Function: Helps the engine control system regulate airflow during idle.
- Replacement reference: Volvo Penta 3843751.
- Aftermarket reference: Sierra 18-7705.
- Installation: Intended as a replacement for the existing IAC motor when the application, connector, and mounting points match.
Part Number Matrix
Use these documented reference numbers when comparing the replacement with the part removed from your engine.
| Brand | Part Number | Role |
|---|---|---|
| Volvo Penta | 3843751 | OEM replacement reference |
| Sierra | 18-7705 | Aftermarket IAC motor reference |
Engine & Model Compatibility
The available catalog evidence identifies this part by its IAC function and the Volvo Penta replacement number 3843751, but it does not establish one universal model, year, horsepower, stroke, or serial-number range. Do not rely on engine displacement alone to determine fitment.
Before purchase, compare the original IAC motor's part number, connector, mounting-hole pattern, body shape, and throttle-body location. When available, verify the complete Volvo Penta engine model and serial number against the manufacturer's parts information.
| Brand | Application reference | Part number | Fitment condition |
|---|---|---|---|
| Volvo Penta | Marine engine IAC motor application | 3843751 | Confirm exact engine model, year, serial range, throttle-body configuration, connector, and mounting arrangement. |
| Sierra | IAC motor replacement | 18-7705 | Cataloged as replacing Volvo Penta 3843751; verify the original part before installation. |
Technical Specs
- Product Type
- Idle Air Control (IAC) motor
- System
- Electronic engine-management and fuel-injection system
- Primary Replacement Reference
- Volvo Penta 3843751
- Aftermarket Reference
- Sierra 18-7705
- Function
- Regulates bypass airflow to help control engine idle speed
- Fitment Verification
- Match the original part number, connector, mounting points, and complete engine application
What's in the Box
- 1 x Idle Air Control (IAC) motor
Only the IAC motor is included unless the order or applicable product options specifically state otherwise. Gaskets, screws, and other installation hardware are not listed as included components.
Installation Notes
- Disconnect the negative battery terminal and follow the engine manufacturer's safety procedures.
- Locate the existing IAC motor on the throttle-body or intake assembly.
- Compare the replacement with the original part before removal, including the connector, mounting points, and airflow passage.
- Disconnect the electrical connector without pulling on the wiring.
- Remove the retaining screws or fasteners and carefully remove the old motor.
- Clean the mating surface and airflow passage as appropriate. Do not force debris into the intake system.
- Install the replacement motor using suitable sealing components if required by the engine manufacturer.
- Tighten the fasteners to the manufacturer's specified torque and reconnect the electrical connector.
- Reconnect the battery, start the engine, and check for air leaks, warning lights, abnormal idle speed, or stalling.
- Complete any idle-relearn or diagnostic procedure specified for the particular engine control system.
Troubleshooting & FAQ
What are common symptoms of a failing IAC motor?
Possible symptoms include an unstable or rough idle, stalling when the throttle closes, an unusually high or low idle speed, and an engine-management warning light. These symptoms can also be caused by vacuum leaks, throttle-body contamination, wiring faults, or other control-system problems.
How can I confirm that this part fits my engine?
Compare the number on the original motor with Volvo Penta 3843751 and Sierra 18-7705, then confirm the connector, mounting arrangement, and throttle-body configuration. For a complete fitment check, use the engine model and serial number with the manufacturer's parts information.
Does the engine require an idle relearn after installation?
Some engine-control systems may require an idle-relearn or diagnostic procedure after replacement. Follow the service information for the specific engine rather than assuming that every application uses the same procedure.
Is this an OEM part?
No. This listing is for an aftermarket replacement IAC motor. Volvo Penta 3843751 and Sierra 18-7705 are reference numbers used for identification and compatibility comparison.
What should I do if the connector or mounting pattern differs?
Do not force the part into place or modify the connector or mounting surface. Stop installation and recheck the original part number, engine model, serial number, and application details.
What are the shipping and return terms?
Available shipping options and delivery estimates are shown at checkout. For return eligibility and warranty coverage, follow the current store policy associated with your order.
Safety & Important Information
- Verify the part number and physical design against the original component before ordering.
- Keep the complete engine model, production year, and serial-number conditions together when checking fitment.
- Do not use a displacement-only match as confirmation of compatibility.
- Disconnect the battery before servicing electrical engine-management components.
- Professional installation is recommended when the required service procedure or diagnostic process is not familiar.
About Sea Sierra
- Marine Parts Focus — Replacement components selected for marine engine service applications.
- Fitment-Conscious Support — Compare the original part number and physical details before installation.
- Global Fulfillment — Shipping options and delivery estimates are presented during checkout.
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