Yingang YG48Q-5A, Maintenance Manual

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YG48Q-5A Maintenance Manual Starting system
134
Major faults diagnosis
Phenomenon Possible causes Solutions

Starting relay
doesn’t attract;

No sound of relay
suction can be
heard while
pressing the start
button, and the
starting motor
doesn't run.

Accumulator voltage too low;

Corresponding fuse is not connected or is
blown;

The Neutral line of the shift position switch
is open circuit

Clutch switch open circuit failure;

Start button open failure;

Flameout switch open circuit failure;

Starting relay failed;

Related lines of the main cable are open.

Recharge the accumulator;

Connect the fuse or replace it;

Connect the line or replace shift
position switch

Connect the line or replace clutch
switch

Connect the line or replace the left
switch;

Connect the line or replace the left
switch

Replace the starting relay;

Repair or replace main cable.

Starting motor
doesn’t rotate: there
is the sound of relay
suction, however,
the motor doesn’t
rotate.

Accumulator voltage too low;

Heavy line connector lug slackened;

Motor open circuit failure;

Open circuit between the terminal contacts
of the starting relay;

Motor short circuit failure;

Engine clogged, motor rotation jammed.

Recharge the accumulator

Fasten the connector lug;

Replace the motor

Replace the starting relay

Replace the motor;

Check the engine.

Motor rotating
speed too low

Accumulator voltage or capacity too low;

Connector lug contacts poorly;
 Starting motor’s output torque is
insufficient
；

Motor resistance too large.

Recharge or replace accumulator;

Fasten the connector lug;

Replace the motor;

Check the engine.