6 replies to this topic

[Vinay-RS]

Hi Everyone, 

 

Today, a colleague and I (not very mechanically oriented ) did some work on my mini. The car was running really rich, and I had thought that the car needed a carb rebuild. We checked the plugs and found that they were black. We then adjusted the jet and the needle until the mixture seemed better.

 

After this the car was idling quite high. (I have a stock 2 clock dash, so couldn't check the exact revs) The next thing we did was adjust the throttle adjusting screw, but this had no effect on the idling speed. After this we adjusted the choke adjusting screw (again with no effect). 

 

Since the car was in need of an oil change and we thought that the air from the crank case breather might have some fuel fumes in it, and that was causing the high idling speed, we changed the oil and the filter. This made the mixture less rich, and the smell of fuel reduced, but didn't seem to affect the idling speed at all.

 

In case the timing was off, we adjusted the advance on the distributor, which helped a little, but too large adjustments made the car sluggish and it tended to keep running after turning it off. At this stage the plugs looked brown and the car feels very responsive apart from the high idling speed.

 

So I was wondering if anyone had experienced anything similar and could suggest a possible course of action.

 

Oh and the car is a stock South African 1275E, with a single 1/2" SU carb.

 

Cheers,

 

Vinay

[robminibcy]

the car ran faster because it was better tuned (ie what you had done made it better! if you can reverse the additional adjustments you made so it runs fast again the idle can be adjusted with the idle adjustment screw which can be found on the front of the carb when looking directly down on it. a google image search should help here!

Edited by robminibcy, 12 July 2014 - 06:55 PM.

[Gremlin]

Have you got any air leaks? Is the butterfly seated correctly?

[Vinay-RS]

the car ran faster because it was better tuned (ie what you had done made it better! if you can reverse the additional adjustments you made so it runs fast again the idle can be adjusted with the idle adjustment screw which can be found on the front of the carb when looking directly down on it. a google image search should help here!

We did adjust both adjustment screws (throttle and choke), with no luck and then only did we check the timing. 

 

Have you got any air leaks? Is the butterfly seated correctly?

There was a leak in the hose from the crank case breather, so we cut the dodgy part of the hose and reattached it, it had an effect, but mostly on the air-fuel mixture. 

 

I think you may be onto something with the butterfly. Turns out the choke cable on my car wasn't attached, so when my friend was reattaching it, he had to tighten the screw for the valve cause it was very loose. 

 

Hence it may have gotten bent. Is there anyway to check it, without actually removing the carburettor, cause I don't have a new gasket.

Edited by deathghost, 12 July 2014 - 09:28 PM.

[Vinay-RS]

Any ideas?

[KernowCooper]

Check the throttle cable has enough free play to allow the idle stop to make contact with the idle screw.

[Vinay-RS]

Check the throttle cable has enough free play to allow the idle stop to make contact with the idle screw.

Sorry for the delay in the response. I was away from the car for a while. You were spot on Dave. Thanks so much for the advice :)