Sierra Engine Parts

Sierra 18-7704 IAC Motor Volvo #8355194

SKU: 4003230 · UPC: 808282287528 · MPN: 18-7704
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02 · Overview

Sierra 18-7704 IAC Motor Volvo #8355194 — Product description

Understanding the Role of Your Volvo Engine's IAC Motor

Keeping your Volvo Penta engine running smoothly starts with precise control over idle speed, and that's where the IAC motor shines. This small but mighty component regulates airflow around the throttle body, ensuring stable idling whether you're docking at the marina or warming up for a long cruise. When it fails, you might notice erratic idling, stalling, or surging RPMs—frustrating issues that disrupt your time on the water.

Engineered as a direct-fit replacement, this Sierra IAC motor steps in seamlessly, restoring factory-like performance without the premium price tag. Boat owners and marine technicians trust it for its reliability in harsh saltwater environments, where corrosion and vibration are constant threats.

Perfect Fit for Volvo Penta Applications

Designed specifically for select Volvo Penta models, this IAC motor matches OEM specifications down to the connector and mounting points. It's a go-to solution for engines experiencing idle control problems, helping maintain optimal air-fuel mixtures for cleaner combustion and better fuel economy.

  • Direct replacement for common Volvo Penta idle air control valves
  • Compatible with a range of sterndrive and inboard setups
  • Resists marine corrosion with durable construction materials

Before installing, double-check your engine's service manual to confirm compatibility, as variations exist across model years and serial numbers.

Key Features That Set It Apart

What makes this Sierra part stand out? It's built with high-quality solenoids and stepper motors that respond instantly to your engine control unit's signals. No more guessing with aftermarket generics that underperform—these deliver precise metering for smooth transitions from idle to throttle.

Close-up of Sierra IAC motor showing durable housing and wiring connector for Volvo Penta engines
Precision-engineered for marine durability and quick response times.

Additional perks include plug-and-play installation, vibration resistance, and longevity that matches or exceeds original equipment. It's the smart choice for preventive maintenance too, especially if your boat logs heavy hours in coastal waters.

Signs Your IAC Motor Needs Replacing

Spotting trouble early can save you from roadside—or waterwayside—breakdowns. Watch for these symptoms:

  1. Engine stalls when coming off idle or shifting into gear
  2. High or low idle speeds that won't stabilize
  3. Check engine light with idle-related diagnostic codes
  4. Rough idle accompanied by hesitation under load
  5. Black smoke from exhaust due to rich fuel mixtures

Regular cleaning helps, but when internal components wear out, a fresh replacement like this one is the fix. Pair it with throttle body service for best results.

Step-by-Step Installation Guide

Swapping out your old IAC motor is a straightforward DIY job that takes under an hour with basic tools. Here's how marine pros do it:

  1. Disconnect the battery and let the engine cool completely
  2. Locate the IAC on the throttle body (usually front or side-mounted)
  3. Unplug the electrical connector and remove the two mounting screws
  4. Clean the throttle body bore with appropriate solvent—no abrasives
  5. Install the new motor, torque to spec (typically 2-3 Nm), and reconnect
  6. Reconnect battery, start engine, and let it idle for relearn cycle

Pro tip: Use dielectric grease on the connector to fend off corrosion. Always scan for codes post-install to verify.

Why Sierra for Your Marine Engine Parts?

Sierra has earned its stripes in the boating world by offering OEM-equivalent parts that undergo rigorous testing. This isn't just another widget—it's crafted to handle the rigors of boating life, from freshwater lakes to salty bays. Owners report fewer comebacks and consistent performance, making it a staple in boatyards everywhere.

"Swapped this in on my Volvo setup last season—night and day difference in idle stability. Worth every minute." – Experienced skipper

Frequently Asked Questions

What engines is the Sierra 18-7704 IAC Motor compatible with?

This motor fits select Volvo Penta engines, particularly those using OEM part #8355194. Verify your model via the service manual or serial number for exact match.

Can I clean my old IAC motor instead of replacing it?

Cleaning can extend life if buildup is the issue, but worn internals require replacement. Use throttle body cleaner and avoid submerging electrical parts.

Will this fix high idle on my Volvo engine?

Yes, a faulty IAC often causes high or unstable idle. After install, perform an ECU idle relearn by letting the engine idle for 5-10 minutes.

How do I test if my IAC motor is bad?

Use a multimeter to check resistance (typically 40-80 ohms) or scan for codes like P0505. Listen for smooth operation when powered.

Does this Sierra part come with a warranty?

Sierra parts are backed by manufacturer warranty—check policy details at purchase for coverage specifics.

Is installation plug-and-play?

Absolutely, it uses the same connector and mounts as OEM, minimizing tools needed. No modifications required.

Can a bad IAC affect fuel economy?

Yes, improper air control leads to rich or lean mixtures, spiking fuel use. Replacement often restores efficiency.

IAC Motor Volvo #8355194


SKU: NVN-4003230
MPN: 18-7704
UPC: 808282287528
03 · The numbers

Technical specifications

BrandSierra Engine Parts
ModelSierra 18-7704 IAC Motor Volvo #8355194
SKU / MFR#4003230

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04 · Before you buy

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05 · Customer voices

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