128000-5720 Aftermarket Caterpillar Starter Motor | Sawley's Select Marine Parts

🔧 Product Description

Aftermarket replacement Caterpillar 3114/3116 OSGR Starter Motor - Replaces Part Number: 128000-5720

New aftermarket Denso-pattern offset gear-reduction starter replacing 128000-5720 for Caterpillar 3114 and 3116 engine applications. The 12-volt, 3.0kW unit uses a 10-tooth clockwise pinion and is supplied as a complete starter and solenoid assembly.

⚙️ Key Features

• 12-volt electrical system

• 3.0kW rated output

• Clockwise rotation viewed from the drive end

• 10-tooth starter pinion

• Offset gear-reduction / OSGR construction

• Complete new starter motor with integrated solenoid

• Marine or engine-grade corrosion-resistant construction

• Direct replacement only after voltage, rotation, tooth count and mounting pattern are confirmed

🧰 Kit / Assembly Contents

• 1 × Complete starter motor assembly - P/N 128000-5720

• 1 × Integrated starter solenoid and shift mechanism

• 1 × Installed pinion gear and overrunning clutch/Bendix assembly

• 1 × Installed armature, field-magnet/winding, brush holder and drive housing

• Mounting bolts, electrical cables and external relays are transferred or renewed separately unless supplied

🔄 Supersession & Cross Reference

OEM Supersession Chain:

• 228000-3700 / 228000-3701 → Later Denso service family replacing 128000-5720/-5721/-5722/-5723

• Caterpillar 10R-0754 / 0R4318 → Service replacements for earlier Caterpillar numbers

OEM / Related Numbers:

• 128000-5720

• 128000-5721

• 128000-5722

• 128000-5723

• 228000-3700

• 228000-3701

• 0R4318

• 10R-0754

• 1053133

• 1119860

• 3E5382

• 9W2946

Aftermarket / Verified Equivalents:

• Denso: 128000-5720 / 228000-3700 family

• WAI/Lester Caterpillar 3114/3116 10-tooth starter family

🚤 Compatibility

Commonly used on:

• Caterpillar medium-duty diesel starting systems

Typically suits:

• Engine / Generator models:

• Caterpillar 3114 marine, industrial and generator engines

• Caterpillar 3116 marine, industrial and generator engines

• HP / Output Range: Engine-rating dependent

• Year Range: Principally 1991-2001; arrangement-number dependent

• Starter Identification: Confirm 12V, 10 teeth, clockwise rotation, 3.0kW output and the mounting nose against the removed starter.

🔌 Function

The starter motor converts battery electrical energy into high-torque mechanical rotation to crank the engine. When the start circuit energises the solenoid, the pinion moves into the flywheel ring gear and the motor turns the crankshaft until the engine starts. The overrunning clutch then protects the starter as engine speed rises.

Common signs of failure / incorrect starter fitment:

• No-crank condition even though the battery and start-control circuit test correctly

• Solenoid clicks but the starter motor does not rotate

• Starter turns slowly, draws excessive current or overheats the battery cables

• Pinion spins without engaging the flywheel ring gear

• Grinding, clashing or repeated pinion kick-out during cranking

• Intermittent cranking caused by worn brushes, solenoid contacts or heat soak

• Corrosion, water intrusion, burnt windings or excessive shaft/bearing play

📦 Condition

• New aftermarket replacement starter motor

• Brand new

• Supplied in original or equivalent packaging