3827501 Volvo.Penta Idler pulley

Illustration 1 g00754851
Typical example (1) Start disable relay (2) Neutral start switch (3) Key start switch (4) Fuse for neutral start switch (5) Fuse for fuel shutoff solenoid (6) Start relay (7) Fuel shutoff solenoid (8) Main power relay (9) Starting motor solenoid (10) Electric starting motor (11) Fuse for key start switch (12) Alternator (13) Disconnect switch (14) Battery (15) Main breaker (16) Starting aid relay (17) Glow plugs (18) Alternator circuit breakerTable 1 shows the maximum acceptable loss of voltage in the circuits. The battery circuit supplies high current to the starting motor.Voltage drops that are greater than the amounts in Table 1 are caused most often by the following conditions:
Loose connections
Corroded connections
Faulty switch contacts
Table 1
Maximum Acceptable Loss of Voltage    
Circuit     Wire label     Current for the circuit in amperes     Maximum voltage drop in volts    
Alternator charging     "109-RD-6"     55 or 90     0.5    
Engine oil pressure switch     -     0.42 maximum     -    
Coolant temperature switch     -     0.25 maximum     -    
Starting aid switch     "109-RD-10"     0.2     0.5    
Glow plugs for three cylinder engines     "877-YL"     13 (1)     0.5    
Glow plugs for four cylinder engines     "877-YL"     13 (1)     0.5    
Battery circuit to starting motor     "101-RD-00"     540 maximum     0.7    
( 1 ) Older engines were equipped with a 27 A glow plug. The 13 A glow plug is the service replacement for the 27 A glow plug. Procedures For Diagnosis Of The Electric Starting Motor
The procedures for diagnosing electric starting motor (10) are intended to help the service person determine if the electric starting motor needs to be replaced or repaired. The procedures are not intended to cover all possible problems and conditions. The procedures serve only as a guide. General Information
The electrical starting system has the following components:
Ignition switch
Transmission Electronic Control Circuit
Start relay (6)
Starting motor solenoid (9)
Electric starting motor (10)
Starting aid switch
Starting aid relay (16)
Glow plugs (17)
Fuel shutoff solenoid (7) The coil of start relay (6) draws about 1 A. Start relay (6) allows current to flow to the starting motor solenoid (9) .Starting motor solenoid (9) is a switch with a capacity of about 600 A. Starting motor solenoid (9) has two functions:
The pinion gear is engaged with the ring gear of the flywheel.
Electric starting motor (10) is rotated.Starting motor solenoid (9) has two coils. The pull-in coil draws about 54.5 A. The pull-in coil is between contact "MTR" and contact "S". The hold-in coil draws about 10.5 A. The hold-in coil is between contact "G" and "S".When start relay (6) closes, the pull-in coil and the hold-in coil receive power. Battery voltage is applied to the terminal "S" of starting motor solenoid (9) . Terminal "G" of the coil is permanently grounded to the ground post or the housing of the starting motor. Grounding for the terminal "MTR" of the pull-in coil is momentary. This ground takes place through the DC resistance of the starting motor.When the magnetic force increases in both coils, the pinion gear moves toward the ring gear of the flywheel. Then, the solenoid contacts close in order to provide power to electric starting motor (10) . When the solenoid contacts close, the ground is temporarily removed from the pull-in coil. Battery voltage is supplied on both ends of the pull-in coil while electric starting motor (10) cranks. During this period, the pull-in coil is out of the circuit.Cranking of the engine continues until current to starting motor solenoid (9) is stopped by releasing the ignition switch.The power that is available during cranking varies according to the temperature and condition of the batteries. The following chart shows the voltages which are expected from a battery at the various temperature ranges.
Table 2
Typical Voltage Of Electrical System During Cranking At Various Ambient Temperatures    
Temperature    12 V System    
-23 to -7 °C (-10 to 20 °F)     6 to 8 V    
-7 to 10 °C (20 to 50 °F)     7 to 9 V    
10 to 27 °C (50 to 80 °F)     8 to 10 V    Diagnosis Procedure
If equipped with electric start, do not crank the engine for more than 30 seconds. Allow the starter to cool for two minutes before cranking again.Never turn the disconnect switch off while the engine is running. Serious damage to the electrical system can result.
If electric starting motor (10) does not crank or cranks slow, perform the following procedure:
Measure the voltage of battery (14) at the battery posts with the multimeter when you are cranking the engine or attempting to crank the engine. Measure the voltage across the battery posts. Do not measure the voltage across the cable post clamps.
Battery voltage
Go to Step 3 if the voltage is equal to the voltage that is given in Table 2 or if the voltage is greater than the voltage that is given in Table 2.
The battery voltage is less than the voltage in Table 2.Refer to Special Instruction, SEHS7633 in order to test battery (14) .A low charge in a battery can be caused by several conditions.
Deterioration of the battery
A shorted starting motor
A faulty alternator
Loose drive belts
Current leakage in another part of the electrical system
Measure the current from the positive "+" battery terminal to starting motor solenoid (9) . Use the 225-8266 Ammeter Tool Gp . The maximum current that is allowed for no load conditions is given in the Specifications module, "Electric Starting Motor" topic.Note: If the following conditions exist, do not perform the test in Step 3 because electric starting motor (10) has a problem.
The voltage at the battery post is within 2 V of the lowest value in the applicable temperature range of Table 2.
The large starting motor cables get hot.The current and the voltages that are specified in the Specifications Module, "Electric Starting Motor" are measured at a temperature of 27 °C (80 °F). When the temperature is below 27 °C