I second what mikes2 said about the relief relay, when it stops just wait and listen for a click from the relay and see if it starts again.you can pop the cover of the relay and look for dampness.

more problems!
 

Since fitting the new leads and charging up the battery i cannot get her to start!
I removed one of the plugs and started her up and could not get a spark. I then put a volt meter on the coil and I've got 12volts when i switch on the ignition. Ive also got a reading on the other side of the coil with ignition on (does this rule out the coil being faulty??) there is fuel present, so am I right to rule out a fuel pump/relay fault?
Ive been told to do a spark test with the 'king pin' lead, will this prove that the ignition coil is ok and that its a distributor or ignition amplifier fault? Ive checked the cap for cracks and all the contacts / rotor arm are clean, the plug on the side of the distributor is a bit iffy, is this the connection to the hall sender? Im thinking that this may be the problem, is it replaceable? can i do a test for this or do I need a new distributor? any ideas????

I had this with my 1.9 GT many years ago. Under the drivers side scuttle area is the ignition Amp with 2 push on round connectors (one I think is from the hall sender). Remove these and check for moisture/ burning and re-attach. Had this on and off for quite a while on mine and ended up changing the pins in the plugs to cure it.
The other item moisture has possibly got into is the hall sender plug on the dizzy, same again, remove clean and re-attach. This area sounds the likely issue as you have 12v on the coil and no spark and as this is a carb engine the fuel pump is mechanical off the camshaft which eliminates that area. Good luck.

I had a fiat 132 many years ago that used to do this. It was a faulty ignition switch. The engine would just randomly cut out, but it started again with another turn of the key.

Also, what about the idle control valve ? (Bosch systems - this is the thing that's partly built into the distributor), and is wired to the ignition amp. I seem to remember the wires for this in the dizzy were very thin and vulnerable to damage. I would have thought if necessary it's possible to bypass this. Sorry for the vague description - it alters the ignition advance retard electronically to compensate for varying engine loads, to keep the idle constant. Some Vauxhalls had the same set up , ie Nova SRs etc.

Water in fuel ? Can you rig up an alternative supply from a can and see if this makes any difference. The symptoms of water in petrol are usually that the car will start and idle fine from cold / standstill, and as you drive off, water begins to move around a bit and gets pulled up into the fuel lines. As it reaches the engine, it misfires and cuts out. Leave it a minute or two and it appears alright until you get half a mile down the road, then it does it again. Rover SD1s and 1980s jap crap were prone to this. Puddle water thrown up by the back wheels got in through rusty fuel tank filler necks.

Some of this not particularily relavent for the 1.9 carb engine, Dizzy has the hall sender in it and thats it. Idleing all done on the carb. This dizzy also still has the vacuum attachment to alter timing for loads as all engines of old did.
If you are getting a good solid 12V at the coil then fusebox and ign switch should be ok. Any fluctuation of the 12v however and i'd be suspecting either the switch or Aux relay as already mentioned.

Thanks again everyone, Im slowly getting there, Just trying to eliminate stuff as I go along. I removed the king lead and cannot get a spark from this either.
Im convinced its the hall sender, Anyone know where I can get some schematics for this car???? A mate (electrical/electronics genius) at work says he can tell me whats wrong using a scope if I can get him some schematics. Is it possible to replace just the hall sender or am I looking at a new dizzy?? Im thinking it may be broken or loose wires to the hall sender.Im also going to replace all the earth conections as well just in case of a bad earth.

If you're not getting a spark from the coil king lead when you hold it to earth when cranking, it's either the coil itself or the coil isn't receiving the switched 12v from the ignition amp

Here is pic of wiring for this section, Very old so hard to make out wires but hope it helps..

cheers !

getting there (i hope)
 

right, coil seems to be ok
The plug with three wires on the side of the distributer (that connects the sensor to the hall sender) seem a bit dodgy, Ive removed the distributer and noticed that the rubber plug is moving freely and the wires can move around and rub against the 'slotted cup' as it rotates. I presume i can press out the gear retaining pin and remove the shaft to get acces to these wires to re-solder or replace.
fingers crossed i find the problem here!
thanks again to everyone who has posted youve all been a great help!
cheers davow