7 replies to this topic

[Pooky]

What is the difference between the idle speed and fast idle speed? What do your mini's idle at?

[Guess-Works.com]

The idle speed is what the engine runs at when the choke is in, when you pull it out, that's the fast idle....

normally a well maintained mini will idle somewhere between 600 and 900 the older they get the less 'happy' the car is to idle slowly... when you start tuning and putting hotter cams in and such like the idle becomes lumpy, and hence it will need to increase to compensate...

[dklawson]

Regardless of engine age/condition, the idle speed is typically happier with a little higher RPM if you're running anything other than a stock cam. My worn out 1275 would idle very smoothly at 600 RPM with its stock cam. I bumped this up to about 900 when I installed the SW5 cam.

[Leonard]

any problems with running a high idle, eg 1500rpm, apart from fuel consumption?

[Dan]

Yes, you won't be able to drive any slower than about 15-20 miles an hour which is not ideal in traffic. As a result you'll wear out your clutch faster.

[dklawson]

You'll probably have dieseling (run on) with an idle speed that high.

[Pooky]

My mini's sometimes not happy idling at all. Sometimes it gets very lumpy on acceleration and can nearly stall at traffic lights etc...it does also run on a bit too, violently sometimes.

Also, is it true that a hot exhaust manifold can evaporate fuel in the carb? Could something like this be the problem?

[themanlegend]

I found that using lead replacement my car ran on really badly... but seems as though my local tesco is stopping LRP that I will have to use it again. Although I realise LRP is supposedly 'C**p' the car doesnt run on.

If its not happy idling you could have a bit of wear in your carb - a refurb kit for 40 quid would sort this out of that was a problem. only a guess there.