I have 'inherited' a Carlton 3000 GSi and have the following problem.
It will start fine 9 times out of 10, although whereas with every other car I have owned turning the key results in instant turning of the starter, on this car there is a delay of around 1 second.
On the other occasion it refuses to start at all with a faint 'relay' (not solenoid) click from behing the dash - the way of resolving this is to 'jump start' the car and it turns over immediately the jump leads are connected.
Any advice would be gratefully appreciated as I am loathe to put a new starter motor in if it is something else.
i was gonna say knackered starter, but then you say it turns over straight away if you hook up some external source of power. So that points the finger to dodgy connections in the king lead to the starter. Youd have nothing to loose by disconnecting the battery and then unhooking all the electrical connections both ends, cleaning them up with some emery cloth and reassembling.