WH 125cc 150cc Relay Starting Motor

Brand: Mortch Motor
Product Code: MIWH125-3079

Product Viewed: 158

Availability: In Stock

Weight: 0.14kg

Packing Size: 6.00 x 7.00 x 7.00cm

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WH 125cc Starter Relay

🔌 Starter Relay · Starter Solenoid · Starter Contactor · Electric Start Component

2-Wire Relay · For 4-Stroke & 2-Stroke Engines with Electric Start · Universal Fit for 50cc-250cc Vehicles

📋 Product Overview

This is the WH 125cc Starter Relay (also known as a starter solenoid or starter contactor) — a 2-wire relay designed for 4-stroke and 2-stroke engines equipped with electric start systems. It is a core component of the electric starting system, responsible for controlling the high-current circuit to the starter motor.

A relay is an electrical switch that opens and closes under the application of a second electrical circuit. In basic operation, the relay controls an output circuit of much higher power than the input circuit. This design allows lower capacity wiring and switches to control high-power circuits, improving system safety and reliability. This relay is suitable for scooters, ATVs, go-karts, and dirt bikes ranging from 50cc to 250cc, making it an ideal choice for starter system repair or replacement.

✨ Core Functions: Control high current with low current · Protect start switch · Switch starter motor circuit · Reliable and durable · Universal compatibility

📐 Specifications

Product Name

Starter Relay / Starter Solenoid

Displacement Range

50cc - 250cc

Terminal Type

2-Wire (2-Pin)

Rated Voltage

DC 12V

Rated Current

100A - 150A

Coil Resistance

Approx. 3-5Ω

Mounting Type

Bolt Mount

Engine Type

4-Stroke / 2-Stroke

Protection

Dust & Moisture Resistant

⚙️ Operating Principle

🔌 Control Circuit

When the start button is pressed, a small current (0.5-1A) flows through the relay coil, generating electromagnetic force.

⚡ Electromagnetic Engagement

The electromagnetic force pulls the contacts closed, completing the high-current main circuit to the starter motor (50-100A).

🔋 Starter Motor Operation

High current from the battery flows through the relay to the starter motor, driving it to crank the engine.

🛡️ Protects Start Switch

The start switch only handles low current, preventing contact burning and extending switch life.

💡 Why is a Starter Relay Needed? Starter motors require very high current (up to 100A or more). If controlled directly by the start switch, the switch contacts would quickly burn out. The starter relay allows low current to control high current, protecting the start switch and ensuring reliable electric starting system operation.

🔧 Compatibility

This starter relay is compatible with the following vehicles and engines:

Vehicle Types: Full-size scooters, ATVs (All-Terrain Vehicles), go-karts, dirt bikes
Displacement Range: 50cc, 70cc, 90cc, 100cc, 110cc, 125cc, 150cc, 200cc, 250cc
Engine Types: 4-stroke and 2-stroke engines with electric start
Compatible Engines: GY6, 139FMB, 147FMD, 147FMF, 150FMG, 153QMI, 152QMI, and various 2-stroke engines
Electrical System: 12V electric start systems

📌 Compatibility Note: This relay features a 2-wire design and is widely compatible with 50cc-250cc electric start vehicles. Before installation, verify that your original starter relay uses a 2-wire configuration with matching terminal sizes.

🔌 Importance of the Starter Relay

🛡️ Protects Switch Contacts

Isolates the start switch from high starter current, preventing contact burning and extending switch life.

🔋 Ensures Starting Reliability

Provides a stable, reliable high-current path to ensure the starter motor receives adequate power every time.

⚡ Simplifies Wiring Design

Allows lower capacity wiring and switches to control high-power circuits, simplifying electrical system design.

🔧 Facilitates Diagnosis

As a key node in the starting system, the relay makes troubleshooting and diagnosis more straightforward.

⚠️ Symptoms of Starter Relay Failure: No response when pressing start button (no clicking sound), starter motor does not turn, starter motor runs continuously (welded contacts), slow cranking, intermittent starting failure, excessive relay heat. If these issues occur, inspect and replace the starter relay promptly.

✨ Product Features

2-Wire Design: Standard 2-wire interface widely compatible with 50cc-250cc electric start vehicles.
High Current Rating: Supports 100A-150A current capacity to meet various starter motor requirements.
High-Quality Contacts: Silver alloy contacts provide excellent conductivity, arc resistance, and long service life.
High-Strength Coil: Premium copper wire coil delivers strong electromagnetic force with quick response.
Sealed Construction: Enclosure is designed for dust and moisture resistance, suitable for harsh operating environments.
Direct Replacement: Drop-in replacement for original starter relay — simple plug-and-play installation.
Universal Compatibility: Suitable for scooters, ATVs, go-karts, dirt bikes, and more.

🔧 Installation & Troubleshooting Guide

Installation Steps:
1. Disconnect the negative battery terminal before starting to prevent short circuits.
2. Remove the original starter relay, noting wire positions.
3. Install the new relay, ensuring it is securely mounted and connections are correct (two small terminals connect to start switch, two large terminals connect to battery positive and starter motor).
4. Reconnect the battery negative terminal and test starting function.

Troubleshooting:
1. If no clicking sound when pressing start button, check the start switch, fuse, and power supply to relay coil.
2. If clicking sound is present but starter motor does not turn, check battery voltage, large terminal connections, and starter motor condition.
3. If starter motor runs continuously, relay contacts may be welded — disconnect battery immediately and replace relay.
4. Ensure all terminals are securely tightened to prevent poor contact, which can cause heat buildup or voltage drop.

⚠️ Important Notice: This product is the WH 125cc Starter Relay with 2-wire design, suitable for 50cc-250cc 4-stroke and 2-stroke engines with electric start. Widely compatible with scooters, ATVs, go-karts, dirt bikes, and other vehicles.
Spec Confirmation: Before purchasing, verify that your original starter relay uses a 2-wire configuration and operates on 12V.
Installation Caution: Pay attention to correct wiring connections. High-current terminals must be securely tightened. Starter relay failure may be caused by other circuit issues (such as a shorted starter motor); perform system diagnosis before replacement. Product images are for reference only; please refer to the actual product.

🔧 Compatibility Notice

Please verify that this part fits your specific vehicle model and year. Many vehicles share similar names but use different components depending on year or market region.
We strongly recommend cross-checking with your vehicle's owner's manual or contacting us for confirmation before placing your order.

📄 Product Disclaimer

Product images, measurements, and descriptions are for reference only. Slight variations in color or appearance may occur due to manufacturing batches or photography lighting—functional specifications remain identical to the ordered part.
Professional installation is mandatory. Mortch Motor assumes no liability for damages, injuries, or losses resulting from improper installation, misuse, unauthorized modification, or abnormal operation.

💰 Import Duties & Taxes

All listed prices EXCLUDE shipping costs, import duties, taxes, and customs clearance fees. These charges (if applicable) are determined and collected by your local customs authority and are solely the buyer's responsibility.
In case of return due to unpaid duties/taxes or refusal to clear customs, the buyer shall bear the original shipping cost, return shipping fees, and any associated administrative charges deducted from the refund.

📌 Order Confirmation: By completing your purchase, you acknowledge that you have read, understood, and agreed to all terms above. For any questions, please contact our support team prior to ordering.