Mitsubishi A3TR0093 Alternator | Volvo Penta 3840181 | 12V 115A

Mitsubishi A3TR0093 Alternator — Volvo Penta 3840181 | 12V 115A

Overview

The Mitsubishi A3TR0093 is a 12V, 115A marine alternator that crosses directly to Volvo Penta OEM part number 3840181. It is the correct charging unit for selected Volvo Penta D4 and D6 diesel engine applications, and Volvo Penta's own electrical-supply catalog identifies the 3840181 as the 12V / 115A alternator for D2-55, D2-75, D4, and D6 configurations. The A3TR0093 features an internal regulator and internal fan, a 6-groove pulley, and clockwise rotation — confirm all identifiers against your existing alternator before ordering.

Compatible Applications

• Volvo Penta D4-180
• Volvo Penta D4-210
• Volvo Penta D4-225
• Volvo Penta D4-260
• Volvo Penta D4-300
• Volvo Penta D6-280
• Volvo Penta D6-310
• Volvo Penta D6-330
• Volvo Penta D6-350
• Volvo Penta D6-370
• Volvo Penta D6-435
• Selected IPS350 / IPS400 / IPS500 / IPS600 applications
• D2-55 and D2-75 (per Volvo Penta electrical-supply catalog for OEM 3840181)

Fitment note: Related Mitsubishi alternators A3TR0091, A3TR0092, and A3TR0094 may share similar housing dimensions but can differ in pulley type, terminal arrangement, rotation, or OEM application. Confirm the exact part number on your existing alternator before ordering.

Terminal Configuration

• B+ — M8 × 1.25
• D+ — M4 × 0.7
• W — M5 × 0.8
• S — spade terminal
• B− — M6 × 1.0

Kit Contents

• 1 × Mitsubishi A3TR0093 alternator assembly
• Mounting hardware not included — reuse existing hardware or source separately

Service Interval

Inspect the alternator at every annual engine service. Replace or rebuild when the charging system shows any of the following:

• Low or unstable charging voltage
• Battery warning alarms or repeated battery discharge
• Insufficient output under full electrical load
• Bearing noise or rough pulley rotation
• Pulley or shaft play
• Internal regulator failure

Before replacing the alternator, verify drive belt condition, cable connections, grounds, and battery health — these are common causes of charging faults that do not require alternator replacement.

Installation Notes

• Disconnect battery power before removal
• Note terminal positions and wire routing before disconnecting
• Confirm belt alignment and 6-groove pulley compatibility with the existing drive setup
• Verify mounting-ear dimensions and bolt pattern against the original unit
• Confirm clockwise rotation matches the engine drive configuration
• Check drive belt condition and tension after installation
• Test charging voltage at idle and under load after installation

Cross-Reference / Alternate Part Numbers

• Mitsubishi: A3TR0093
• Mitsubishi: A003TR0093
• Mitsubishi: A3TR0093ZC
• Volvo Penta (primary OEM): 3840181
• Volvo Penta (secondary reference): 3803911 — verify applicability; 3840181 is the strongest confirmed Volvo Penta cross-reference to A3TR0093
• Lester: 12745
• Arrowhead: 400-48216

Related Parts

• Volvo Penta Alternator 3840181 — OEM equivalent
• Browse all Volvo Penta Marine Engine Parts
• Electrical & Accessories

Technical FAQ

Is A3TR0093 a direct replacement for Volvo Penta 3840181?

Yes. Mitsubishi A3TR0093 (also listed as A003TR0093) is the direct Mitsubishi Electric cross-reference for Volvo Penta OEM part 3840181. Both are 12V / 115A units with a 6-groove pulley and internal regulator.

What is the difference between A3TR0093 and A003TR0093?

These are alternate catalog formats for the same Mitsubishi part. A003TR0093 is a longer format used in some cross-reference catalogs; both refer to the same alternator.

Can I use A3TR0091 or A3TR0092 instead?

Not without verification. These related Mitsubishi alternators may share housing dimensions but can differ in pulley groove count, terminal arrangement, or rotation direction. Confirm the exact OEM part number before substituting.

What should I check before replacing the alternator?

Check drive belt condition and tension, all battery cable connections, ground straps, and battery health. A failing belt, poor ground, or weak battery can cause charging symptoms that mimic alternator failure.

Does this alternator fit twin-engine installations?

Each engine uses its own alternator. On twin-engine boats, confirm the part number for each engine independently, as port and starboard engines may have different alternator configurations depending on the accessory fit.

Is 3803911 the same as 3840181?

3803911 appears in some aftermarket cross-reference catalogs alongside A3TR0093, but 3840181 is the primary and most clearly documented Volvo Penta OEM cross-reference. Verify 3803911 applicability against your engine's parts documentation before relying on it as the matching number.

Parts Desk Insights

Best use case: The A3TR0093 is the correct alternator for Volvo Penta D4 and D6 diesel applications where the OEM unit is 3840181. It’s a well-documented aftermarket source for this charging position and is the right choice for boaters looking to replace or upgrade the charging unit on these engine families without sourcing the OEM part directly. The Volvo Penta OEM 3840181 is also available if OEM sourcing is preferred.

Common customer questions: The most frequent point of confusion is the 115A rating alone — customers sometimes assume any 12V/115A alternator will fit. The 6-groove pulley, 47 mm pulley diameter, terminal layout, and Volvo Penta 3840181 cross-reference are what confirm the correct fit. Customers should also note the 3803911 reference: it appears in aftermarket catalogs but 3840181 is the stronger OEM match. If a customer is unsure, ask for the existing alternator part number from the unit itself or from the engine room label.