Mini 998 Running on

[casbar]

My sons 89 Mini Mayfair's engine runs on when the ignition is switched off.

Now my knowledge is a bit hazzy, as its been a while since I've had a car with a distributor etc.

Is this a timing issue, ie too far advanced or retarded. Or is this likely to be something else causing the problem

[fastcarl]

usually advanced timing causes this , but hew could have a build up of carbon on the piston tops hot enough to ignite the mixture even after shut off.
dont late minis have an anti run on valve fitted??. thtas if it is a late model.

carl

[casbar]

Our's is an 89, so I'll have to check the Haynes Manual.

No manual says 1990 Cooper on for valve

Plus side, I had a 1991 Cooper once, and that ran on as well, so I suppose the valve didn't work that well

Edited by casbar on Wednesday 20th December 19:05

[wildoliver]

Check timing, if ok it is probably in need of a decoke.

The correct way of doing a decoke is to take the head off etc, however there are some things you can run the engine on to clear it out a bit. I'm not advising you to do so though! Bizzarely white spirit seems to do the trick, added to a tank of fuel, discovered this while checking to see what the professional bottles of decoke/injector cleaner contained.

[Plotloss]

Mines an 89 and has a habit of doing this every now and again.

Timing more often than not.

[casbar]

Haynes suggest 8 deg at a 1000 revs, is that correct?

Was going to stick a strobe on it today, until I realised it needed to get power from the bat, which is in the boot, so the leads won't reach - suppose I could run a couple of fly leads forward, or take power from somewhere in the engine bay

[wildoliver]

Just get a second battery and run it off that, doesnt need to be the car battery its only to power the strobe

[casbar]

Yeah thought of that, or I could run it off a power pack

[fastcarl]

connect the strobe to the big main feed to the starter ,its perm live.


carl

[sporelife]

Check the type of plug, as they may run too hot for the engine, creating a hot spot for detonation with the ignition switched off.

I had this problem on my 998 (mildly tuned to 63Bhp) and have changed to a cooler plug which has minimised run-on.

[casbar]

Going to check the timing over the weekend, and I'll check the plugs then - Thanks

[inim]

In general your Mini is out of tune and it could be in more ways than 1, ignition timing mixture etc. Most people don’t think about having their car tuned. The only way to do this is to take your Mini to a rolling road. This is expensive by the hour but you should only need 1 hour to properly set the car up. Before you do this you need to make sure that the car is fully serviced and replace all things electrical such as plugs, points, leads, rotor arm, distributor cap and filters etc. A source of good value parts is www.ukclassicminiparts.com This will be the best money you will ever spend on your Mini and you could get 20-30% more power. This happened to me.