Hyundai HYBCF31 User Manual (English)

Rachel CardenasJul 29, 2025

How to fix a Hyundai HYBCF31 that won't start?

D
dillondanielsJul 29, 2025
If your Hyundai Trimmer won't start, begin by checking if the switch is in the ON position. A blocked fuel filter or fuel supply could be the issue; clean or replace them. If the fuel mixture is too rich, open the throttle valve and clean or replace the air filter. For carburetor, electrical problems, or bad electrode spacing, it's best to consult your distributor. Also, clean or replace contaminated or defective spark plugs, ensuring the gap is adjusted to 0.6 to 0.7 mm if the electrodes are contaminated.

Hyundai HYBCF31 Specifications

General

Engine Type	1E139F - Air cooled, four stroke, single cylinder petrol engine
Engine Size cc	31
Oil Capacity ml	310
Fuel tank capacity ml	600
Rated Power kw	0.7
Fuel Ratio/Fuel Type	Unleaded regular
Noise Level dB	113
Rated Speed rpm	6000
Drive Type	Direct
Start Method	Recoil
Clutch type	Centrifugal type
Rotation direction	Counter-clockwise (viewed from top)
Cutter head	Brush Cutter: 255mm, Grass Trimmer: 430mm
Cutter blade mm/teeth	1.6 /3
Cutting Width mm /Length mm /Diameter mm	255 Brush cutter/430 grass trimmer

Weight and Dimensions

Gross Weight kg	8.5
Dry Weight kg	7.0
Fully Assembled Dimensions L x W x H	1820 x 750 x 500
Extensions mm/kg	N/A
Box Dimensions L x W x H mm	1070 x 300/105 x 295

Summary

1. SAFETY

1.1. General Safety Notes

Operator responsibilities, safe operation, manual retention, and symbol meanings.

1.2. Carbon Monoxide Hazards

Information on carbon monoxide poisoning symptoms and prevention methods for outdoor use.

1.3. Fuel and Electrical Safety

Covers fuel flammability, fueling procedures, and electrical safety precautions.

1.4. Battery Safety

Risks associated with battery electrolyte leakage, acid burns, and proper handling procedures.

1.5. Vibration and Noise Hazards

Risks of vibration exposure and protecting hearing from machine noise.

1.6. Additional Safety Instructions

Covers proper usage, operational safety, PPE, and maintenance warnings.

2. QUICK START

2.1. Initial Setup and Contents

Lists product components and provides an overview of the quick start process.

2.2. Handlebar and Trigger Assembly

Instructions for assembling the trigger and handlebar controls onto the machine.

2.3. Guard, Blade, and Drive Shaft Attachment

Steps for fitting the trimmer guard, blade, and connecting the cutting assembly to the drive shaft.

2.4. Spool Line and Fuel/Oil Preparation

Guidance on installing spool line and adding fuel and oil before operation.

3. STARTING PROCEDURE

3.1. Pre-Start Checks and Fueling

Ensuring correct fuel/oil levels and setting the power switch before starting.

3.2. Priming and Choke Operation

Using the primer bulb and choke lever for cold or warm engine starts.

3.3. Recoil Starting

The procedure for pulling the recoil cord to start the engine, including choke adjustments.

4. STOPPING PROCEDURE

4.1. Engine Cool-down

Allowing the engine to cool down before shutting off to prevent damage.

4.2. Machine Shutdown

Steps to safely stop the engine by releasing the throttle and switching off power.

5. USING THE MACHINE

5.1. Accessories and Harness

Guidelines for using original accessories and wearing the shoulder harness correctly for safe operation.

5.2. General Trimming Techniques

Best practices for trimming, including engine speed, cutting motion, and deck positioning.

5.3. Safe Operation and Usage

Covers clearing the work area, avoiding slopes, and proper handling of the machine.

5.4. Specific Trimming Scenarios

Techniques for trimming around trees and extending the cutting cord.

6. MAINTENANCE

6.1. Routine Checks and Lubrication

Covers daily, weekly, monthly checks, and lubrication for key components.

6.2. Engine and Fuel System Maintenance

Details maintenance for engine oil, bevel gear, air filter, and fuel system components.

6.3. Air Filter and Spark Plug Service

Procedures for maintaining the air filter and servicing the spark plug.

6.4. Blade and Idle Speed Adjustment

Instructions for sharpening trimmer blades and adjusting engine idle speed.

6.5. Storage and Transportation

Guidelines for preparing the machine for storage and safe transportation.

7. TROUBLESHOOTING

7.1. Engine Start Issues (Fuel Related)

Addresses problems with fuel delivery to the carburetor and cylinder, and rich fuel mixture.

7.2. Engine Start Issues (Spark Related)

Covers no spark issues due to switch, wiring, plug gap, contamination, or defects.

7.3. Engine Performance Problems

Solutions for engines that turn but stall, fail to accelerate, or won't start after other checks.

8. SPECIFICATION

8.1. Technical Data

Provides detailed technical specifications including engine type, size, power, and dimensions.

10. DECLARATIONS OF CONFORMITY

10.1. EC Declaration of Conformity

Official statement confirming the product's compliance with relevant EU directives and noise regulations.

14. WARRANTY

14.1. Warranty Terms and Exclusions

Details on specific warranty terms, exclusions, and how to obtain hard copies.

Hyundai HYBCF31 User Manual

Table of Contents

Questions and Answers: