Morris Minor Owners Club

I haven't come across this issue before and any help would be appreciated.

Last year I changed my car to Negative Earth. Since then the starter motor has not turned over with the same vigour. It turns over almost as if the battery charge is low. I have checked the Battery and it is ok. Has anyone else come across this? I know I can replace it, but I prefer to fix things if I can, replacing as a last option.

I know there are some electrical gurus out there. Could it be, for instance, that the Armature has retained some residual magnetism from the old polarity and that this is offsetting the new current? If it does, would removing the brushes (so the motor doesn't spin) and holding the starter button out for a spell remove it.

At this stage I'm just 'flying kites' to come up with a reason for it. So any help would be appreciated.

first thing to check is that all the battery leads and the solenoid / battery wires are in good condition and making good contact, as moving them could have caused problems (eg. poor connection or fraying wire etc..)

hi, have you tried bench testing your starter motor with negative earth and see if it actually works? all you have to do is basically get a car jump starter with th jump leads attached, place the positive on the positive terminal on the starter motor and the negative on the body of the starter motor, once youve done this you will need to get a piece of wire (insulated) and connect it to the already connected positive jumper and find a connector on th starter motor , the starter motor will growl at you as it spins round, if this works theres niothing rong with it and you neednt replace it! i no this for a fact as i have done it many times before on changing polarities and just generally testing my electrical equipment! if youve dun this motor works, u replace it but nothing still happens, try changing the contacts on the terminals to the vbattery with sum new ones you can get from Halfords! charly

I would say that you have disturbed some connections somewhere.

Changing polarity should make no difference at all and the starter is not polarity sensitive anyway (turns the same way whichever the polarity). Any residual magnetism will be really tiny and have absolutely no effect, certainly at those current values.

Check all connections are good. Don't forget that coincidences do sometimes happen and maybe the starter is beginning to give up.........