Installation Guide for 12V 1.4KW Bobcat / Kubota Lester Starter Motors

I. Pre-Installation Preparation

Confirm Model Compatibility

• Verify starter specifications: 12V/1.4KW, consistent with the original equipment parameters.

• Common Bobcat starter models: 6685190 (11-tooth), 6667987, etc.

• Common Kubota Lester starter models: 77700-11716, etc.

Safety Measures

• Disconnect the negative (-) terminal of the battery to prevent accidental startup and electric shock.

• Wear protective gloves and goggles.

Tool Preparation

• Socket wrench (matching bolt specifications)

• Torque wrench (accuracy ±5%)

• Sandpaper/steel wire brush (for cleaning contact surfaces)

• Grease (for splines and bearings)

• Multimeter (for circuit inspection)

II. Bobcat Starter Installation Steps

Remove the Old Starter

1. Disconnect all connecting wire harnesses and mark their positions.

2. Remove the three fixing bolts (usually located at the drive end and housing).

3. Carefully take out the old starter to avoid collision.

Install the New Starter

1. Clean the mounting surface to remove oil stains and rust.

2. Align the new starter with the flywheel ring gear, ensuring a gear clearance of 2-4mm.

3. Insert the three mounting bolts and hand-tighten them.

Tightening and Wiring

1. Tighten the bolts to the specified torque (34-38Nm/25-28ft-lbs).

2. Connect the B+ terminal (thick red wire) of the solenoid switch to the positive terminal of the battery.

3. Connect the control terminal (S) to the starter relay.

4. Ensure all wire harnesses do not come into contact with moving parts.

III. Kubota Lester Starter Installation Steps

Remove the Old Starter

1. Disconnect the connecting wires and mark their positions.

2. Remove the fixing bolts (usually 2 M10 bolts).

3. Take out the old starter and clean the mounting surface.

Install the New Starter

1. Apply grease to the armature splines.

2. Align the starter with the flywheel ring gear and insert it into the bolt holes.

3. Hand-tighten the bolts to ensure the starter fits tightly against the engine.

Tightening and Wiring

1. Tighten the fixing bolts to the specified torque (45±5Nm).

2. Connect the B+ terminal (battery positive terminal) with a torque of 12±2Nm.

3. Connect the control wire (usually red) to the starter switch.

4. Inspect wire insulation to avoid short-circuit risks.

IV. Common Precautions and Key Parameters

1. Mechanical Installation Key Points

2. Electrical Connection Key Points

• Wiring Sequence: First connect the B+ terminal of the solenoid switch, then the control circuit, and finally the negative terminal of the battery.

• Wire Gauge: Use copper wires of not less than 8AWG (cross-sectional area ≥8mm²) to ensure sufficient current-carrying capacity.

• Insulation Protection: Ensure all joints are well-insulated without exposure.

• Wire Routing: Avoid wire harnesses coming into contact with heat sources such as exhaust pipes.

3. Post-Installation Testing

1. Check that all bolts and joints are secure.

2. Briefly activate the starter switch (for no more than 5 seconds) and observe if the starter operates normally.

3. The interval between consecutive starts should be ≥10-15 seconds to avoid overheating damage.

4. After startup, check for abnormal noise or vibration.

V. Special Reminders

• Bobcat-specific Notes: Some models (e.g., 753) use three fixing bolts; ensure accurate positioning during installation.

• Kubota-specific Notes: The fixing bolt positions of certain models (e.g., RTV series) are special, and other components may need to be removed for access.

• General Taboos: Do not strike the starter housing during installation to avoid damaging internal parts.

• Long-term Use Recommendations: Regularly check if the starter fixing bolts are loose and keep the wiring terminals clean and free of corrosion.

Summary

References：

Sources of Technical Information

I. Sources of General Safety and Operational Specifications

• Disconnecting the negative battery terminal: A fundamental safety requirement for all electrical maintenance, derived from standard operating procedures in the automotive maintenance industry.

• Startup time not exceeding 5 seconds, with an interval of ≥10-15 seconds: A technical specification from starter motor manufacturers to prevent overheating and motor damage.

• Prohibiting striking the starter housing: A general warning in equipment maintenance manuals to protect the precision internal structure of the starter.

II. Sources of Bobcat Starter Installation Guidelines

1. Removal Steps for Bobcat 753 Starter

2. Bobcat Starter Models and Specifications

3. Bobcat Starter Installation Torque (34-38Nm)

III. Sources of Kubota Lester Starter Installation Guidelines

1. Kubota Starter Models and Specifications

2. Kubota Starter Installation Torque (45±5Nm)

3. Kubota Starter Installation Steps

IV. Sources of Key Technical Parameters and Precautions

1. Gear Clearance Requirement (2-4mm)

2. Wire Gauge Requirement (≥8AWG)

3. Lubrication Requirement (Applying high-temperature grease to splines and bearings)

V. Comprehensive Source Explanation

• Bobcat Official Workshop Manuals: Service manuals for models including 753, S250, and S300.

• Kubota Official Workshop Manuals: WSM (Workshop Manuals) for models including OC60-E2 and L3560.

• Construction Machinery Industry Standards: SAE J542 Starter Motor Installation Standard, QC/T 731 Automobile Starter Motor Standard.

• Automotive Maintenance Technical Specifications: Professional textbooks such as Structure and Maintenance of Automotive Electrical Equipment and Structure, Principle and Maintenance of Automotive Starters.

• Equipment Manufacturer Technical Documents: Installation instructions and torque parameters provided by starter manufacturers (e.g., Valeo, Denso).

Note: For precise installation details of specific models (e.g., the number and position of fixing bolts), refer to the original equipment manufacturer's (OEM) workshop manual for the corresponding device. Minor variations may exist between equipment from different batches.