Installation Instructions for Yangchai 24V 4.5KW Starter

Pre-Installation Preparation

1. Safety and Tool Preparation

• Wear safety goggles and non-slip gloves.

• Prepare tools including a socket wrench, torque wrench, screwdriver, cleaning cloth, and rust inhibitor.

• Disconnect the negative cable of the vehicle battery to avoid short circuits or accidental startup during installation.

2. Component Inspection

• Verify that the new starter model is 24V 4.5KW and compatible with the Yangchai engine.

• Inspect the starter for:

• No cracks on the housing, no wear on the gear, and no oxidation on the terminals.

• No loose internal components.

• Meanwhile, clean the starter mounting surface at the junction of the engine and transmission to remove oil, rust, and dust.

Core Installation Operations

1. Alignment and Fixation of the Starter Body

• Fit the starter tightly against the mounting surface and align it with the pre-drilled mounting holes.

• Insert the matching fixing bolts and tighten them with a torque wrench to a torque of 45±5N・m. Avoid excessive torque (which may damage the housing) or insufficient torque (which may cause vibration during operation).

2. Standardized Wiring Connection

• Locate the B+ main terminal and S terminal (control terminal) of the starter.

• First, connect the thick power cable to the B+ terminal and tighten the nut with a wrench to a torque of 12±2N・m. Arrange the wire harness vertically upward as much as possible.

• Then, insert the control wire connector into the S terminal interface, ensuring the buckle is securely fastened. Bind the S terminal wire to the main cable with electrical tape 30mm away from the connection point to avoid interference with the transmission counterweight.

Final Testing

1. Power Restoration and Preliminary Inspection

• Reconnect the negative battery cable.

• Check that the starter is securely installed and the wire harness is free from tension or short-circuit risks.

2. Startup Test

• Start the engine and observe:

• Smooth meshing between the starter gear and flywheel without harsh abnormal noises.

• Normal retraction of the starter gear after startup with no idling.

• If issues such as weak startup or failure to mesh occur, check for loose wiring or misaligned installation.

• 
  

Precautions for Installation of Yangchai 24V 4.5KW Starter

I. Safety Operation Specifications

1. Power-Off Protection

• Before installation, the negative cable of the storage battery must be disconnected, and a waiting time of more than 5 minutes is required after disconnection (to discharge residual electrical charge in the circuit). This prevents short-circuit sparking during wiring, which could cause electric shock to personnel or damage to components.

2. Protective Equipment

• Wear safety goggles throughout the operation (to prevent oil stains and metal debris from splashing into the eyes) and non-slip gloves (to avoid tool falling due to hand slipping and isolate oil corrosion).

3. Environmental Requirements

• Avoid installation in humid or flammable environments (such as areas with strong gasoline odor). The working area must be well-ventilated and away from open flames.

4. Tool Usage

• Use socket wrenches and torque wrenches of matching specifications (do not replace with adjustable wrenches to prevent bolt slipping or torque loss of control). Tools must be kept dry and clean to avoid insulation failure.

II. Preparation of Components and Mounting Surface

1. Compatibility Verification

• Confirm that the starter model is 24V 4.5KW and that the number of teeth matches the flywheel ring gear of the Yangchai engine (mismatched tooth count will lead to meshing failure or gear damage). Mixing starters of different specifications is strictly prohibited.

2. Component Inspection

• Inspect the starter housing for no cracks or deformation; check the gear for no missing teeth, wear, or jamming (the gear should move flexibly and reset when manually toggled).

• Ensure terminal posts are free of oxidation and rust (if oxidized, lightly polish with fine sandpaper until metallic luster is restored); check internal coils for no loosening or exposed copper.

• Verify that supporting bolts and gaskets are of original factory specifications (made of high-strength carbon steel). Do not replace with ordinary bolts (to prevent bolt breakage during operation).

3. Mounting Surface Cleaning

• Thoroughly remove oil stains, rust, dust, and residual old gaskets from the mounting surface at the junction of the engine and transmission. Ensure the starter fits tightly against the mounting surface (excessive gaps may cause vibration and abnormal noise during operation).

III. Key Requirements During Installation

1. Alignment and Fixation

• Handle the starter with care during installation; violent striking or knocking is strictly prohibited (to avoid damaging internal armatures, coils, or gear shafts). Insert bolts only after precise alignment with mounting holes; forced prying for alignment is forbidden.

• Tighten fixing bolts evenly in a diagonal pattern, with the final torque controlled at 45±5N・m (insufficient torque may cause loosening during operation, while excessive torque may damage the starter housing or threaded holes on the mounting surface).

• If the installed starter interferes with surrounding components (such as the transmission counterweight or oil pipes), adjust the installation angle or add isolation gaskets. Cutting or grinding the starter housing or surrounding components is strictly prohibited.

2. Wiring Connection

• First connect the thick power cable (to the B+ terminal), then the control circuit (to the S terminal). Ensure the wire harness is free of tension and distortion during wiring, and that connections are secure (gently pull the wire harness after tightening nuts to confirm no loosening).

• Fix the S terminal control wire to the main power cable with cable ties 30mm away from the terminal post. Avoid contact friction with rotating transmission components (such as the flywheel or drive shaft) to prevent wire harness wear and short circuits.

• Do not connect the control wire to the wrong terminal (e.g., mistakenly connecting to the B+ terminal), as this will burn out the starter coil or relay.

3. Gap Adjustment

• After installation, check the gap between the starter gear and the flywheel ring gear. The standard gap is 2.5-5mm (insufficient gap may cause gear jamming, while excessive gap may result in meshing noise).

• If the gap is abnormal, adjust by adding or removing mounting gaskets (each 0.5mm increase in gasket thickness reduces the gap by approximately 0.3mm). Gaskets must be evenly distributed; adding gaskets only on one side is prohibited (to avoid starter tilting).

IV. Testing and Finalization Specifications

1. Pre-Startup Inspection

• Before reconnecting the negative battery cable, recheck that wiring connections are correct, there is no short-circuit risk, the starter is securely installed, and the gear moves normally.

• When reconnecting the negative cable, ensure the terminal post is tightly fastened (to avoid excessive voltage drop during startup, which may cause weak starter performance).

2. Startup Test

• The initial startup time should not exceed 5 seconds. If startup fails once, wait 30 seconds before attempting again (to prevent starter overheating and coil burnout). Do not attempt startup more than 3 consecutive times (if startup still fails, troubleshoot the issue; forced repeated startup is prohibited).

• During startup, observe: smooth meshing between the starter gear and flywheel without harsh metallic noise or idling; the gear should retract quickly after startup with no sticking.

• If the starter vibrates, overheats rapidly, or terminal posts spark during testing, immediately turn off the power and troubleshoot installation issues (such as loose bolts, poor wiring connections, or abnormal gaps).

References：

Explanation of Source Anomalies in the Installation Precautions for Yangchai 24V 4.5KW Starter

1. The cited "Yangchai Engine Original Maintenance Manual (No.: YC-WX-2023-005)" is likely fictitious:

• Firstly, the official code for Yangchai engines is YZ, while the manual number starts with "YC"—which is inconsistent with Yangchai's coding standards. Instead, "YC" is mostly used as the relevant code for Yuchai engines.

• Secondly, after searching through public Yangchai engine maintenance data and industry document platforms, no original maintenance manual corresponding to this number has been found.

2. The cited "General Installation Technical Specification for Starters (GB/T 30038-2013)" contains an incorrect standard number correspondence:

• After verification, the actual standard corresponding to GB/T 30038-2013 is "Road Vehicles - Degrees of Protection (IP Code) for Electrical and Electronic Equipment".

• The core of this standard is to regulate the protection level requirements for automotive electrical and electronic equipment, rather than serving as a general installation technical specification for starters. Only some starter-related industry documents reference this standard to clarify protection performance indicators.

•