6 replies to this topic

[I-B-Quick]

I've been trying to reset my timing and mixture and I think I'm almost there. ( I hope to get it all checked on an RR soon ) but need to get somewhere roughly correct to get the MOT sorted.

It just tends to run on a bit after the ignition is turned off. Is it likely timing issue or mixture ? or both.

It appears to run well enough on the road - pulls cleanly etc. Temp gauge has it sitting bang on the "N" when driving but it has been a hot day so not sure if that is still too hot.

Any suggestions greatly received.

[karl & his cooper]

Mine over runs if ive pulled over with high revs and turn engine off. Ill get over run. Might be diff to your problem.

[Ethel]

It's got pre ignition. High compression ratio, over advanced ignition, lean mixture, all contribute.

[T.Harper]

It's quite common, especially in HC engines. see here

[mab01uk]

To cure running on my 1275 Mini completely, I fitted an anti-run on valve (from the breakers) as fitted to the brake servo bracket on later Rover Mini Coopers and most 1275cc Metros. It just needs a live ignition fed wire from the fusebox so that the valve opens the inlet manifold to air when you turn off the engine, making it impossible to keep running. Also of course an earth connection and vacumn pipe to the inlet manifold take off or a Y piece connection into the existing brake servo vacumn hose.
Rover fitted this setup after the introduction of unleaded fuel which I believe runs hotter, worth doing as running on can damage your crankshaft bearings and pistons.
A temporary fix is to pull the choke fully out for a short time before switching off a hot engine, the cooling rich mixture is often just enough to stop the pre-ignition happening.

Edited by mab01uk, 09 June 2008 - 06:15 PM.

[Pauly]

Could be also a build up of carbon ontop of the pistons, red hot carbon sitting ontop of the pistion, mixed with petrol and it wil ignite like it was the spark plug.

Paul.

[T.Harper]

If your ignition timing is set up correctly you can simply solve this by pressing the accelerator as you turn the key to turn the engine off, so that when the engine is off you are essentially flooring it. Stops run-on. Simple and easy