it started out that it would run heaps rough everynow and then and then it would cut out while still rolling in gear and after a few seconds it would turn itself back on and back fire as if i had switched it off then back on. then it wouldnt run unless i kept the key turned to starter motor. any ideas? i am gonna try replacing the points but thats all i can really think of?

i had a similar problem, worn ignition switch and also old wiring harnes/plugs on wires to the ignition switch, replaced switch and also used individual snap in plugs for each wire insted of block connector.

Sounds like it could be points or condensor.

Has it got fuel??
Dont laugh, I went into a mates shed the other day and he had just got his $15,000 motor back in to his HZ ute
Its a 355 with all the bells and whistles.
It was ran in on an engine dyno and ran great,
Butin the ute just wouldnt run.
Ge was saying it ran for a few seconds now it just back fires. He had adjusted the timing, it was perfect.
After a bit of looking around we discovered there was only fuel in the secondarys he had been pumping all the fuel out of the primarys, but when you pumped the acclorator a little bit of fuel would make it out of the secondarys just enough to get it to fire and that would be it, and when we looked in the carby and pumped the throttle we would see fuel cime out just enough to confuse us enough to chase else where, little did we know there was no fuel in the primarys because there was no fuel in the fuel tank........

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The "key" to this seems to be the fact that it is necessary to turn the key to the starter position to allow it to run.
Some cars have a by-pass from the input side of starter solenoid [from the ignition switch] to the output side of the ignition resistor, to bypass it during starting. If the current flow from the ignition switch, to the resistor is interupted [dud swirch, broken wire etc.] then the engine will start while the starter is engaged, but will not continue to run when the switch is released to the "ign" position.

Is this what is happening to you?

Replacing the points may well be a good idea if they are worn, but i suggest that they have nothing to do with this problem you have, & how one links the starter position of the switch to the ignition points defeats me entirely.

Have a real good look at the ignition switch. Use the workshop manual to allow you to test the various circuits through it. If it is dud, replace it.
If it is proven to be good, then the manual will tell you the colour marking of the ignition wire. Check it to see if it is OC [open circuit] If it is, then fixing the break, or re running a new one should solve the problem.

I'll agree with the others, check out the wiring first before buying points & condensor or other 'maybe' parts.

My original thinking was: When you have the ignition swith at 'S', the ballast resistor is bypassed, giving the coil 12V (less the voltage drop from the cranking). If the points are weak, the extra bit of voltage might help.

Unplug the ignition switch and try hotwiring it. If the ignition switch is defective, it will run fine when hotwired.

hehehe "hotwire it", you say that like all Datto owners know how to hotwire cars.. ..ok you might be right..

When my ignition switch stuffed up, I replaced it with a headlights switch. I put it in the cigarette lighter hole. Pull out one click for ignition, and 2 for start.

I then went and bought another ignition switch soon after. It was just to get me through the week.

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you say that like our little dats are not "probably the easiest car there ever was to hotwire"

everythings conviently exposed and colour coded ready to go

not that i have ever done it yet...

i replaced the ignition barrel and it started but now it is stuffing up again, it will only start rarely and when it does it runs for a little then cuts out and you cant start it again, there is fuel in the carby etc. and the spark plugs and point look alright but i havent had a chance to check them properly.