6 replies to this topic

[Wayne93]

Hi there, I hope you can help me! I am having trouble with my mini when idling after a cold start, the engine seems to try to get into a rhythm but it splutters fails and it has actually stalled whilst standing before if I don't rev the engine sufficiently. This problem is only apparent for a short period of time however, once it starts to sluggishly move away there eventually seems to be a sudden burst of power after a few seconds as if the engine is then receiving sufficient fuel and the problem rectifies itself. This only happens when starting her up after she's been stood for a good few hours (overnight etc) and not after warm starting or during the journey. Please can you give me any indication as to what the problem may be. it's a 1989 998cc Mini Mayfair.

Thanks, Wayne.

[Chris wood]

Hi Wayne,

I have exactly the same symptoms and in trying to fix it, i have replaced serviceable parts in the carb including the waxstat - do you have one of these (i'm running a 998 with HS2)

There is an idle screw that will enhance tickover speed but i find that it when i get it running correctly at cold, the idle is too high when hot (nearing 1500)

Interested if you get to the bottom of it, I just use a bit of choke to get running and by the time I get to forth gear it's all fine. Perhaps the choke setting need tweaking?

[Matt29992]

Mine also does this, i just allow it to run on choke for a few minutes to let it all warm up. Best to let old cars warm up anyway before driving them anyway

[Wayne93]

Hi Chris, mine has a HS4 fitted to it I believe, I was considering removing it and doing a mini strip and service as I have read that it may be gunked up on the inside which is only overcome when the engine warms and the revs increase. My idle is sitting at around 1000rpm when cold and only fluctuates up by a couple of hundred RPM when warm to around 1200/1250. I adjusted the idle screw to try and rectify the problem and also tweaked the carb to increase the fuel flow which at the time worked wonders when it came to exhaust note and road performance yet I got in this morning and she was reluctant to pull off again! I use the choke to pull away but it seems to have the same result, (sluggish, stuttering, non-responsive) it doesn't usually take too long to get into rhythm, usually after a few hundred yards when the engine suddenly bursts into life! I may have to just follow your advice Matt until I get to the bottom of it.

[Chris wood]

Sorry i meant HS4 carb, you can buy a service kit from mini spares which isnt expensive and it comes with all the parts required to re-furb it including gaskets. To clean mine, i bought a can of carb cleaner, a firm toothbrush to scrub it with then washed it all out in paraffin... I got a bit carried away while it was off the car and got the autosol and drill attachment out to make the whole body and fuel pot shine :)

Once your happy the mixture is set correctly (light brown spark plugs) I would leave it alone and concentrate on thing like choke adjustment and idle screw. Out of interest what needle are you running / is it all standard?

For info, I put a stage one kit on mine with an AAU needle (running a K&N pancake filter). I was advised this would be too rich, but works a treat with my set up. If you don't have one, I would say get the carb cleaned, serviced and then install a stage 1 kit :)

[Wayne93]

I have seen those kits, it might be a very worthwhile idea and I don't blame you doing some aesthetic work on it whilst it's off the car as it's a pain to do anything to it whilst it's fitted! It's a standard needle I believe, only recently purchased the car and it seems like the carb has never been touched, I have replaced the air filter element on the engine though to a K&N as the old paper one inside the air cleaner housing was filthy. I've ordered new spark plugs for her as the old ones are showing their age so I should be able to get a clearer colour indication off them as to whether it is too rich or too lean which may point me in the right direction. I've got a fuel filter on the way from Minispares aswell, the one fitted doesn't look like it's the correct one judging by what I've seen on other Minis out there and looks quite suspect so it may be another issue to consider. And yes a stage 1 kit is definitely on my list of priorities!

[crf150]

I have a 1991 mini city and it is running a hs4 carb with a heavier red spind and red needle if I can remember right. Mine doesn't seem to be idling properly, it pulses could this be because air is getting in from somewhere ? New gaskets need ? it doesn't seem to be doing it as much when it is warm but when it's cold I have the choke on, it will be sort of idling and then the rev would get a bit higher and the it would go back down again. Any help ?