My '91 Cooper (Carb.) often runs on after I turn off the ignition, sometimes for up to a couple of seconds, sometimes not at all. Any idea where I should start in attempting to remedy this? If its tuning can I do it myself?
Incidently it seems to get through more fuel than I had anticipated and I noticed there was a faint smell of fuel when it was running. Regards, Gwilym.
Sounds like it's in need of a good crypton tune, and don't forget to add a bit of oil into the carb dashpot. I've got the same type of Cooper as you and I know their fitted with anti-run on valve's and to be honest i've never had running on problems with mine, touch wood. But for now rev the engine up a bit just before you turn the key to off and this will help the carb burn up the residue fuel left in the carb and stop it running on until you get it tuned.
Hope this help.
Taffy
If you look in Google Groups you'll find a thread in this newsgroup that discusses running-on in some depth.
It sounds like you have two problems. Running-on and excessive fuel consumption are usually not related. It's probably a good idea to check your fuel pump for leakage.
Running on is usually caused by hot spots in the combustion chamber. These can be caused by lean running or over-advance of the ignition.
Cheers,
Kelley
HI!
Is your idle too high? A worn jet will also cause poor consumption and running on, not too much hassle to change but you will need to take the carb off so it would be wise to buy a rebuild kit and do the lot in one go!
Has it always done it? if it is only recent then you can expect it to be a reasonably simple job to sort out, but when you say 91 carb, I wonder whether you have one of the MG metro engined coopers, these tended to diesel quite badly as the beak in the combustion chamber got quite warm and ignited the fuel, the only solution then would be to remove the head and apply the grinder :-)))))
The carb rebuild is the easiest option but by all means make sure you have given it a good service first! the thermostat is often overlooked, so for £2 it is well worth changing for peace of mind because the engine will have a tendancy to diesel the hotter it runs.
Hope that adds to the fun!
miniman
Do Coopers have an anti-run-on valve like the MG Metros? If so it could be knackered
Thanks everyone for the help, its not an RSP so not the metro engine.
Its not idling high normally but the accelerator pedal is sticking a bit causing high revs during gear change etc... which I guess explains the higher fuel consumption but didnt know it could cause the run on.
Regarding the thermostat wouldnt I know if that was faulty through the temp gauge showing high? (which it isn't). If not which thermostat should I go for 74, 82 or 88C.
The radiator looks a bit rusty inside and I have to top it up, not sure if thats a factor. Will definately be changing the plugs any recommendations? Also need to get the K&N filter in some cleaning fluid.
Thanks, Gwilym.
If you have a K&N, and have not had a needle change and mixture adjusted (ideally on a rollong road), you could well have a weak mixture (even if the K&N is really dirty), which would cause combustion chamber hot spots and hence running on. On my competition engine, I leave it in gear and lift the clutch just after switching off (with the parking brake firmly on or my foot on the brake pedal!).
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overlooked,
The best plugs to fit are NGK's and will last at least 12,000 miles with no problems, at least they do on mine.
Taffy
I cured my run on by retarding the ignition to about 12 BTDC this also allowed me to run the carb at 12 flats down on the mixture nut.
the rich mixture was covering up the miss fire that occurred when I had the carb set to 12 flats.
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