Morris Minor Owners Club

My 1098 keeps running on after it is turned off. The timing is at about 3 deg BTDC using a timing light.
Any ideas?

Has it had a decoke recently? Glowing bits of carbon can have this effect. Another possibility (though unlikely) is that if you have electronic ignition there might be a backfeed from another circuit which keeps enough juice to run the ignition.

It could be that the mixture is too weak.

Have a look at the plugs, if they are very white it's likely that the mixture is too weak and so things are locally overheating. If they are black it is likely that you have carbon deposits and need a decoke. The good news is that you might be able to avoid having the head off 'cos if it's too weak just adjust to be richer. If it's too rich run it weak for a while and see if the carbon will burn off;-)

The first stop in these cases is always to lower the speed of the
tickover. If you have a dynamo then the red 'charge'light should
be just glimmering on tick over

Thanks for the input, no, not electronic ignition. Decoke could be favourite, although I will try reducing the tick over as well.

or you could just stall it when you switch off ;) i know someone who does that with a midget (highly tuned but uses bog standard 95 octane U/L)

Advance the ignition slightly until you hear it 'pinking' - then retard very slightly. Also - try a new set of plugs. Failing that - try a different brand of petrol - say Shell or Esso , rather than supermarket brand.

Found this topic on search, I've had this problem since i got my mog. I run it on branded petrol (usually esso or shell), tried redex on advice of a friend which did nothing, ive brought the idle as far down as i can, the mixture is fine, could it be the timing is too far advanced?

Could be. Could also be carbon build up, or plugs running too hot.

I have more probs with running on when using 95 octane (especially the local Tesco stuff) than I do when using Optimax, and also when driving in very slow moving heavy traffic instead of being able to keep up a bit of speed.

When it's running on I usually just stall it in gear, hate the noise of an old engine clacking away backwards!

I had running on problems when I got my traveller, probably due to 27 years of the previous elderly lady owner driving slowly ;)

Tried everything, in the end taking the head off for a decoke did the trick.

Since I've been driving the car the head hasn't coked up at all ;)

I used to find Hebe ran on when the mixture and idle speed weren't quite right, or when she got hot. I suspect the decoke would have helped but we'll have to see what the head is like when I take it off eh? ;)

Incidentally, running on due to a coked up head is often referred to as "dieseling" because the bits of glowing carbon/soot act a bit like the glow plugs in a diesel car and act as the source of ignition.

I do put super unleaded in now and again as it seems to like that but doesnt seem to help much with the running on, how do i know if my plugs are running too hot?. By the way I had an unleaded cylinder head fitted a while ago so surely it couldnt be coked up already?

Usually timing too retarded - advance it till it 'pinks' - then take it back slightly. Some also suggest de-coking by sucking a cup of water through the engine - via the wee tube going to the vacuum advance on the dizzy. Obviously you take it off at the dizzy - leaving it attached at the manifold - and place the loose end in the cup. This to be done at very fast idle on a hot engine - and well away from home !! The other cure is to just give the thing a really good thrashing - no carbon build up then !

Thats why i dont think its coked up as it does get a thrashing! Like the other weekend i went down to eastbourne and back 4up and when i got home it still ran on! Would sucking water through an engine not do any damage? Redex came highly reccomended by a friend who owns a couple of mach I escorts, i tried putting it in the fuel and the 'intensive' teatment several times, it didnt really affect the running on but it certainly ran a little better. What should the timing be set to? Should it be different to whatever the workshop manual says if it has an unleaded head?

Do what BMC suggested, the official timing point is only for starters as there
are many variables which apply to an individual car. Advance the ignition
until you get slight pinking when pulling hard in top gear up a SLIGHT incline and then take it back slightly. For your info eleven clicks on the A/R wheel
on the dizzy equals one degree.

Ok will do! Should i advance the ignition until it pinks while idling and then take it for a run after ive retarded to make sure its not pinking under load?

No - absolutely not - never heard an engine pinking at idle, but I suppose there is a first time for everything! Just do as Willie details it - slight pink in top gear on upslope, then retard a little. In fact i run mine so it 'just' tinkles slightly as I put my foot down - at this point the engine is advanced by the vacuum system, and it takes a split second for that advance to fall away when I open the throttle - and so i get that slight 'tinkle', which tells me I am just right! And I have no running on.