car not running as it should

[Tezm8]

hi guys,
my 1960 Morris Minor with a 1098cc A series engine has not been running properly for the last week or so. i have not much experience yet with working on the car and don't have massive amounts of knowledge on Minor engines so was wondering if someone could give me a few tips on getting to the bottom of the problem. my car starts fine and runs fine for 20mins driving or so but after a period of time it starts to misfire and splutter until it stalls and doesnt start up again until its rested and cooled for 10mins. what should i do? it usually stalls when slowing down or stopping at a junction if that helps. thank you.

[67-2door]

Hi there,
I had a similar issue with my previous morris when I first bought it. It turned out I had two separate faults, fuel vapourising in an in line fuel filter that someone had fitted near the pump (it was quite a hot summer too at the time). And also a failing condenser that would work ok when cold but cause a misfire & rough running when it warmed up.
My money would be on the condenser.
Cheers.
Neil.

[bmcecosse]

Could be many things... vacuum in the petrol tank is a possibility... so take the cap off next time it happens and listen for air sucking in. But it can also be the condenser/points/ rotor arm , but it won't be the coil ! Try the simple things first... But only change ONE thing at a time !

[irmscher]

Its never the coil .I would be careful buying new repro parts condenser etc as they have a nasty habit of failing or not working whatsoever

[horologiumwatches]

It does sound like the coil failing to me, but then I must be wrong as it's NEVER the coil!
Possible condenser, but money is on the coil. I had a similar one once, developing a misfire when warm and mending itself when cold. The only thing I tried was changing the coil for a spare and it was fine.

[bmcecosse]

It can be dirty/loose coil connections - but it's NEVER the coil...unless it has been damaged and leaking oil....

[autolycus]

... or unless someone has fitted the wrong type of coil in the past. Even if the box says it's the right one, you must check the primary resistance by disconnecting the terminals and measuring the resistance between them. Search this forum for views on the correct value.

Kevin

[bmcecosse]

Yes indeed - you are looking for 3 / 3.4 ohms across the two LT terminals.

[Tezm8]

Thanks for your comments guys turns out someone had fitted the wrong coil so I swapped a coil from a mates old mini and she is running brilliantly. Cheers Tezm8.

[bmcecosse]

Just check the ohms on that coil too - Minis after ~ 1980 have ballast ignition and use a 1.5 ohm coil. Which will quickly destroy itself on a non-ballast ignition system.