Cat 303.5E CR Start motor and electric problems

[Cat303]

Hi everyone !

A few days ago wir tried to startup our Cat 303.5E but it won´t crank.
We just got a clicking sound from the start motor.

After we replaced it with a new we had still the same problem.
We checked all fuses,relais and ground connection.
Everthing seems fine. We even replaced the battery with a bigger definitely working one and tried seperatly to start with a start booster directly connectet to the start motor.
Same clicking problem again.

After we found a small flap which we could partially see the flywheel through, we could see that the start motor tries to engage the flywheel, tries to turn but won´t do it properly.
Then the starter will try it again and again, thats where the clicking sound comes from.

After that, we bypassed the signal from the ignition switch on the starter motor.
Well now the whole electrical system is dead.
If we try to turn the key to startup the bordcomputer nothing happens.
We checked fuses and relais again but everything seem fine.

Do anyone have ideas on that ?

Thank you

 

[KenMac]

Check for a main inline fuse between the battery and starter. May or may not be there, but no harm in checking. Some have them.

 

[Nige]

If you would like an electrical schematic to help you with your diagnostics then post a machine Serial Number.

 

[Simon C]

Might be an idea to voltage drop those battery cables, positive and negative, as they have soldered lead ends that burn off internally on some. Check if the battery terminals are lead or not. If they are, costs nothing to test and it needs to be ruled out. Look at the schematic Nige sent you and the resettable breakers are worth checking out along with the fuses.
Simon C

 

[Cat303]

Hey,
The Serial number of the machine is : RKY00886
An electrical schematic is highly appreciated.
Battery terminals are lead. So we will check them, and if we find the resettable breakers.
Fuses are checked and should be ok.
thank you guys for the ideas an tipps !
Raphael

 

[Nige]

The Serial number of the machine is : RKY00886
An electrical schematic is highly appreciated.

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