MGB starting problem

[shaunmorris]

MGB would not start yesterday after a normal run out. stopped for petrol and then car would not turn engine over. Called recovery who claimed alternator was not charging so jumped started the car and drove the 3 mile home. I put the battery on charge and it holds 13 volts fully charged. started engine just and noted that voltmeter across battery was reading 13.5 volts which tells me the alternator is charging. I now find that the with a fully charged battery car will not turn over, I suspect the starter motor, any thoughts anyone ?

[PoleDriver]

Have you checked the cables are tight on the battery/starter motor/starter solenoid?
Can you hear an initial click when you try to engage the starter?

[Stickyfinger]

Most likely, check would be the starter motor brushes/dirt/bad earth, quite common.
but first check the main earth cable, if its old it is often rotten or the contacts have rusted under the clip, does it get hot when you start the car ?

[shaunmorris]

All connections seem good, I have noticed that the red ignition light is not coming on when you turn on. prior to starting as normal.

[Geordie MGmike]

sounds like you have more than one problem.
If a fully charged battery only just starts the car the battery may be faulty (assuming the AA man jump start worked well) or possibly the starter motor, cables etc. Measure the voltage across the battery when cranking and if it drops below 10v change it.
The ignition light might be just a bulb blown but if not it points to an alternator fault. Again get the meter out and check the voltage at the alternator "Ind" terminal. It should be 0v when the engine is not running and 12v (or above) when running. 12v at rest is an alternator diode pack fault.

Edited by Geordie MGmike on Sunday 9th August 19:20