32 replies to this topic

[Lt-SilverDragon]

When I pull out the choke and start the engine it runs well and I can rev it without a problem, when I put the choke in it will run for about 30 seconds maybe a minute before it dies and if I try and rev it while it's running then it splutters and dies. Sometimes I can catch it by fully depressing the accelerator pedal. Also the pedal itself feels really loose, it's kinda wobbly and is really easy to puch down. Hopefully somebody can enlighten me on what might be wrong, I'm guessing the throttle cable or something along those lines because the choke increases the revs no problem maybe it's the timing?

[ianbunyan]

Is the exhaust / manifold blowing at all?

[Pooky]

sounds to me like your cable needs adjusting

is it a carb?

[Tompo]

Sounds like a fueling problem could you have a build up of C**p in the carb or blocked injectors or a dodgy fuel pump?

is there definatly fuel getting to the carb/injectors?

[Pooky]

we're stupid! If he's got a choke it'll be carb!

has this only happened recently?

i'm putting my money on throttle cable/idle adjustment

[Jammy]

Have you got a rev counter? A mini should idle at 750rev/min. Altho you can set it up to 1000rev/min.

If it is not idling slowly your mixture might be a bit lean, especially if pulling the choke out keeps it going. Do you have a colourtune? If not, whip out the plugs and see what colour they are.

[Lora222]

sounds like the carb, i had a similar problem, the mini wouldnt start easily without the choke being out, then if i put the choke in it would be revving too low then conk out.

my throttle and choke cable were apparently too tight or something like that, after some fiddling with the carb all is okay.

[Lt-SilverDragon]

Yes it is a carb, it's a 86 Mini Piccadilly and it's stock. I only bought this a few weeks back as a project basically and it's been off the road for a few years so I don't know how long it's been doing this.

It runs well when the choke is pulled out, even only a little bit so it must be getting petrol and air and the exhaust is fine.

How do I adjust the mixture on the carb? I'll try that and see if that helps.

Sorry but whats a colourtune? I doubt I've got one so I'll try and take the plugs out but I probably don't have a socket deep enough. If it's lean it will be whitish right?

The thing that threw me off is the loose accelerator pedal, will that just need tightening?

Cheers for the help

[Jammy]

The accelerator pedal is held on by one bolt I think. How do you mean loose? You mean you can wiggle it around or that you can depress it slightly without it affecting the revs of the engine?

A coloutune is a spark plug type thing that you put in place of one of the spark plug and glows different colours depending on whether your mixture is rich or lean.

There will be two ways of adjusting the mixture depending on which carb you have. It will either be the HIF38 or the older HS4. Is there a float bowl on the side (like a little pot on the drivers side of the carb that the fuel line goes to)?

[Pooky]

i'd think it'd be a HS4...

what speed does the car idle at with the choke out? it should be about 1100 or maybe a little bit more, if this is so then your fast idle is ok.

I'd then check a) your throttle cable

the pedal itself feels really loose, it's kinda wobbly and is really easy to puch down

that's not right! lol

B) your throttle adjusting screw
c) jet adjusting nut

[Lt-SilverDragon]

I can shake the accelarator pedal from side to side, not alot but I can and the pedal is really easy to puch down I can't feel any pressure against my foot.

Yeah I think it will be a HS4, when I'm standing infront of the mini there a cylindrical part attaching to the carb it has two tubes going into it.

I don't have a rev counter so I can't tell what the revs are when the choke is out.

[Jammy]

Then you have the HS4. Does the car seem to idle really slowly?

One thing I forgot was whether there was any oil in the dashpot! Under the black nut on top of the dashpot and then bring the piston up and then push down, there should be some resistance when you push it dowm. If there isn't top it up with some engine oil, 3-1, or transmission oil.

I can't really recommend messing with the mixture unless its clear that the mixture is the problem. When you adjust either screw, try and remember how many times you've turned it so you can put it back to how it was if it doesn't cure the problem.

IIRC, the idle screw should be passenger side of the carb and near to the manifold (but right next to the dashpot), and screwing it inwards (down) will increase the idle speed. Run the engine til it is warm and will start without the choke, then turn the idle screw a quarter turn at a time. If you adjust it til the engine is revving quite high and its still dying then it is probably the mixture.

The mixture screw is part of the assembly that comes out the bottom of the carb. You need to screw the nut (I think its the one directly underneath the spring) in (or upwards) a quarter turn at a time. Do this until the engine will idle without dying.

[Jammy]

With regards to the loose accelerator pedal, the only thing I can think of is that the accelerator return spring might be old and loose or something. If you can replace the spring. Its located on the end of the accelerator cable, and hooks into a washer type bit and a bracket that is bolted between the carb and the manifold.

[Lt-SilverDragon]

Thanks for the help Jammy but no luck so far. I checked the dashpot and yes there was resistence so thats fine and I looked for the idle screw and I think I found it, I couldn't see another screw around the area so I'm guessing that was it. I tried screwing it in but it didn't seem to make a different I turned it three completes turns before deciding to put it back to its original position.

I did try to start it with the choke out a tiny bit and it fired up and ran, probably would of ran all day if I'd let it but as soon as I touched the accelator it died, I tried it a few times and exactly the same thing hapened. With the choke out (about halfway maybe less) it will start up and I can rev it with the accelaror without anything happening.

I didn't risk messing with the mixture.

On a side note, will my mini take unleaded petrol? I looked in the handbook but it didn't mention it.

[Jammy]

Sounds like it is the mixture then, I can't think of anything else it would be. I did think it might be an air leak, but if it was then it wouldn't matter whether the choke was out or not.

As to whether it is unleaded. There really isn't anyway of knowing without pulling the head off, I can't remember when they started putting unleadeded heads on minis but I think it was the late 80s.