# 21103642 Starter Motor | Genuine Volvo Penta Part

## 🔧 Product Description

A genuine Volvo Penta 12-volt reduction starter motor for D9 and selected D11 marine diesel installations. It supersedes starter 3801284 and combines the solenoid, reduction gearing, armature and overrunning drive into a high-torque unit capable of cranking the large-displacement diesel at starting speed. Mounting pattern, pinion geometry and electrical system voltage must match the original starter.

## 🚤 Compatibility

Typically suits:

-   Volvo Penta D9A2L MH
-   Volvo Penta D9A2M MP

-   **Engine Family:** D
-   **HP Range:** Approximately 575 HP
-   **Year Range:** Approximately 2004-2010 D9A2 production; verify starter mounting and original unit by engine serial number

## ⚙️ Key Features

-   12-volt heavy-duty reduction starter for D9/D11 diesel engines
-   Integrated solenoid engages the pinion and switches cranking current
-   Reduction gearing produces high cranking torque with controlled current draw
-   Current service replacement for Volvo Penta 3801284
-   Pinion, mounting flange and cable-terminal positions must match the original unit
-   Engine type: 9.4-litre inline-six marine diesel, 12-volt starting system

## 🔌 Function

Converts battery power into high-torque rotation of the flywheel so the diesel reaches the cranking speed required for compression ignition.

## ⚠️ Common Signs of Failure

-   Solenoid clicks but the engine does not crank
-   Slow cranking with correctly charged batteries and sound cables
-   Pinion spins without engaging the flywheel
-   Intermittent no-crank caused by worn solenoid contacts or brushes
-   Grinding, excessive current draw or heat at the starter terminals

## 🛠️ Service Notes

-   Disconnect the batteries before touching starter cables, and label the main and control connections as they come off
-   Inspect the ring gear teeth before fitting a new motor; a chipped or worn ring gear will ruin the new pinion
-   Mount the motor square on clean faces with whatever shims the installation uses, so pinion engagement matches what the workshop manual for your engine specifies — never leave shims out to make it fit
-   Clean the main and earth terminals back to bright metal, tighten to the specified figure and refit the insulating boots; a great many failed starters are really voltage drop in the cables and earth path
-   Crank with the engine unable to start first, listening for clean engagement and release, then feel the terminals for heat after several attempts

## 🔄 Supersession & Cross Reference

### OEM Supersession Chain

-   21103642 → Supersedes 3801284 → Supersedes 3803873 → Supersedes 3803842

### OEM / Related Numbers

-   3801284 earlier number superseded by this part
-   3803873 earlier number superseded by this part
-   3803842 earlier number superseded by this part
-   3849004 - 12-volt starter relay
-   21308514 - insulating bushing
-   21780397 - associated wiring harness
-   21546674 - cable kit

### Other-Brand OEM Numbers

-   Mitsubishi M009T72779 / M9T72779

### Aftermarket / Verified Equivalents

-   API Marine / Sterndrive Engineering: 1506914
-   Rareelectrical: replacement starter for 21103642 / 3801284
-   AS-PL: S5313S

## 📦 Condition

-   Genuine Volvo Penta part
-   Brand new
-   Supplied in original or equivalent packaging

## Details

- **Price:** 2436.58 AUD
- **Vendor:** Volvo Penta
- **Tags:** Volvo Penta

## Variants

| Variant | Price | Available |
|---------|-------|-----------|
| Default Title | 2436.58 AUD | In stock |

## Images

- 21103642 Starter Motor | Genuine Volvo Penta Part

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> Source: [Sawley's Auto and Marine](https://www.sawleysautoandmarine.com.au/products/21103642-starter-motor-genuine-volvo-penta)
> Updated: 2026-08-22