17 replies to this topic

[Disco Dan]

Mini MK4 1982

HS4 Carb - has been cleaned up and all the settings are screwed up.

Right now it idles fine, but the mixture is off and the dashpot oil needs changing to something much lighter.


I managed to find info about the mixture - adjusting nut for mixture etc

But what is the initial settings to start from?

I have read in manual to turn mixture nut until engine speed changes then back it off a turn for correct setting. But mine stays the same regardless of what I do to the nut.

Everything on the carb appears and feels tip-top- all the bushes/seals/gaskets etc

So does anyone know what settings I should put the car too to set it up? ie 2 turns from top for mixture, 1 full turn for idle etc.

Cheers!

It started at initial pos setting. but very rough and only for about 5 seconds then died - and that was only with full choke. Have not been able to start it since.

I removed the float bowl cap and found someone had put two gaskets on it - presumably to raise the float? Also I noticed a small indentation in the bottom of the float where it touches the valve. Is that meant to be there? The float appears to be working correctly, also the fuel is def getting to the carb. There is a strong smell of fuel - which I thought could be flooding (was not as I waited an hour and tried again) or over rich mixture. But it only started very rough and briefly with full choke?

I turned the mixture richer by 2 turns and it started again for about 5 seconds - but again this was only with full choke.

What have I done wrong?

Edited by Disco Dan, 08 January 2009 - 11:11 PM.

[Dan]

Search for SU initial position. I'm not typing it all again.

[Lund]

Mini MK4 1982

HS4 Carb - has been cleaned up and all the settings are screwed up.

Right now it idles fine, but the mixture is off and the dashpot oil needs changing to something much lighter.


I managed to find info about the mixture - adjusting nut for mixture etc

But what is the initial settings to start from?

I have read in manual to turn mixture nut until engine speed changes then back it off a turn for correct setting. But mine stays the same regardless of what I do to the nut.

Everything on the carb appears and feels tip-top- all the bushes/seals/gaskets etc

So does anyone know what settings I should put the car too to set it up? ie 2 turns from top for mixture, 1 full turn for idle etc.

Cheers!

Set the jet approx 0.050" from the bridge (piston damper and needle out) turn the engine overand adjust from there.

Its better to have a rich mixture than a lean one - as a lean mix can do alot of damage. Try using 3in1 oil in the dashpot.

[Disco Dan]

Search for SU initial position. I'm not typing it all again.

Cheers, will do.

Set the jet approx 0.050" from the bridge (piston damper and needle out) turn the engine overand adjust from there.

Its better to have a rich mixture than a lean one - as a lean mix can do alot of damage. Try using 3in1 oil in the dashpot.

Cheers will give it a go in the morning!

[Dan]

Don't set it to approximately anything, set it to the initial position. It's a specific setup designed to make the carb work and from there it is easy to tune the fuelling. If it's not in the right position to start with tuning will take much longer.

[Disco Dan]

Cheers Dan,

Link here for future reference:

http://www.theminifo...nitial position

[Disco Dan]

It started at initial pos setting. but very rough and only for about 5 seconds then died - and that was only with full choke. Have not been able to start it since.

I removed the float bowl cap and found someone had put two gaskets on it - presumably to raise the float? Also I noticed a small indentation in the bottom of the float where it touches the valve. Is that meant to be there? The float appears to be working correctly, also the fuel is def getting to the carb. There is a strong smell of fuel - which I thought could be flooding (was not as I waited an hour and tried again) or over rich mixture. But it only started very rough and briefly with full choke?

I turned the mixture richer by 2 turns and it started again for about 5 seconds - but again this was only with full choke.

What have I done wrong?

Edited by Disco Dan, 08 January 2009 - 10:53 PM.

[Disco Dan]

I have tried searching for this topic but the search function on this site if very 'odd'. It seems you cannot type in "SU" as it is too short a word ! I thought this was a mini forum? lol

Tried searching for carb carburetor HS4 setup etc etc but nothing. And yes I did read the FAQ on searching - but it was quarbled, confusing and quite frankly harder to understand than the inflight manual for Air Belgium.

So I am sorry if this is an annoyingly repetitive topic - but the search function sucks!

Edited by Disco Dan, 08 January 2009 - 11:16 PM.

[Dan]

That's OK, at least you've tried to use what's already written here!

Remove the second gasket from the chamber, that will indeed raise the fuel level by about 3mm in the chamber which in turn raises it in the jet. That is awful and is going to massively overfuel, in fact I wouldn't be surprised if it was running straight through the carb and into the inlet as liquid fuel with it that high. There shoudn't be a dent in the float as far as I remember but it's been a couple of months since I took one apart. I'll have a look at one when I can. If you take one gasket out it should work fine, unless there is a problem with the float.

Sorry about the problems. The FAQ is gong to be dismantled soon and re-built (I haven't discussed this with the others yet but hey-ho) becuase it is confusing and there is too much unrelated stuff in there. Unfortunately anyone can put things there and stuff ends up there that's never been asked at all. As for the search, it's been fixed many times but there's always something wrong with how it works.

[Disco Dan]

That's OK, at least you've tried to use what's already written here!

Remove the second gasket from the chamber, that will indeed raise the fuel level by about 3mm in the chamber which in turn raises it in the jet. That is awful and is going to massively overfuel, in fact I wouldn't be surprised if it was running straight through the carb and into the inlet as liquid fuel with it that high. There shoudn't be a dent in the float as far as I remember but it's been a couple of months since I took one apart. I'll have a look at one when I can. If you take one gasket out it should work fine, unless there is a problem with the float.

Sorry about the problems. The FAQ is gong to be dismantled soon and re-built (I haven't discussed this with the others yet but hey-ho) becuase it is confusing and there is too much unrelated stuff in there. Unfortunately anyone can put things there and stuff ends up there that's never been asked at all. As for the search, it's been fixed many times but there's always something wrong with how it works.

I removed the gasket. Returned the mixture back to two turns off level. Fuel is level with the top and 'just' seeping out. Can hardly see it but when I dry it off with a rag I can see it flow out a little.

I assume now I am looking at a float problem?

The indentation in the underside of the float does not look 'original'. I would say the indentation is causing the fuel level in the chamber to be a tad higher than it should - thus allowing it to seep ever so slighty into the carb chamber all by itself?

...I will attempt to 'repair' the dent in the float with a soldering iron.

Thanks for you help!!

Edited by Disco Dan, 08 January 2009 - 11:57 PM.

[Dan]

A new float isn't expensive, even if you have to get one from here it could get to you very quickly. It sounds very much like a fuel level problem. Is the chamber sitting fairly level in the car? If it was from another car originally it may have the wrong spacer and so be sitting at the wrong angle. Check that the needle valve under the float hasn't been packed out with a washer too, although that would drop the level. Make sure it's the right valve as well.

[Disco Dan]

A new float isn't expensive, even if you have to get one from here it could get to you very quickly. It sounds very much like a fuel level problem. Is the chamber sitting fairly level in the car? If it was from another car originally it may have the wrong spacer and so be sitting at the wrong angle. Check that the needle valve under the float hasn't been packed out with a washer too, although that would drop the level. Make sure it's the right valve as well.

Yes that is true - however the only mini wreckers within 100km has been closed up since before the christmas period started (laid back here!). Minispares is the only other source of parts I know - that is painfully slow, usually 6 weeks from time I order before the good arrive. I have just ordered about NZ$700 worth about 2 days ago and they have yet to ship it or charge my card yet!

...would be nice to have a quick repair since it is Friday afternoon, I'll need my car working well by Monday for work!

I have to rely on a repair without any parts and without being able to leave my house!!

Pictures coming very soon...

[Disco Dan]

OKay here is a few pictures - hopefully this will shed a bit more light on the problem:

Edited by Disco Dan, 09 January 2009 - 02:53 AM.

[Disco Dan]

Dont worry about the bit of pipe in the middle picture!! Just a spacer for the breather to fit on!

[Disco Dan]

Can someone tell me:

Looking down the hole of the jet (first picture) I can actually see the level of the fuel in there - when I lower the jet right down. It is sitting about 3mm from the collar.

Should it be level with the collar?? If so, I believe that would explain why the previous owner used two gaskets to try and increase the level?

Could I have the wrong float valve in it? - ie wrong length