11 replies to this topic

[stevelane]

I have an hs4 carb on a 1992 mini city e.

The mixture is running too rich, the plugs are black, so I've tried to use a colourtune plug to set it correctly.

However, I keep backing it off and the car stalls with the flame still orange and the only way to keep it running is to turn up the idle speed.

Can anyone give me some tips or pointers as to where I'm going wrong?

[HarveyT]

try turning the idle speed first using the idle adjusting screw and then setting the mixture strength, that could be why your not able to get it bang on because when the mixture is correct the idle speed is too slow.

[stevelane]

Sorry I'm confused. Do you mean turn it up before setting the mixture?

[gazza01]

yes that's what he meant I think.

[stevelane]

I'm not sure. The engine is already running fast when I start and then just suddenly stalls, it's not like it slows with each turn and then dies

[KernowCooper]

Use the lifting pin on the side, revs up and stays up = to rich stalls of dies away= to weak, engine revs rise slightly and settles back your in the ball park. Obviously you should only carry out any adjustment of the carb after a engine tune, including tappets.

[stevelane]

Valve clearances and timing have both been set and checked, just mixture I'm having problems with

[stevelane]

Use the lifting pin on the side, revs up and stays up = to rich stalls of dies away= to weak, engine revs rise slightly and settles back your in the ball park. Obviously you should only carry out any adjustment of the carb after a engine tune, including tappets.

Where do I find the lifting pin? And don't I have the same problem of keeping it going whilst I'm doing this?

[stevelane]

I have a haynes manual for su carbs up to 88 and have located where it says the piston lifting pin should be but I can't actually see it in the carb, as the car is 92 is it possible that it doesn't have one? Other threads suggest this may be the case but no confirmation

[Stiggytoo]

It can be a bit of a pain to locate. But if it is an Hs4, standing at the front of the car, reach around the left of the carb. The lifting pin will be in there somewhere below where the piston is.

Edited by Stiggytoo, 16 April 2014 - 10:27 PM.

[jime17]

I think they may have done away with the lifting pin by 1992.

[KernowCooper]

yes some carb bodies dont have the pin, in which case lift the revs higher on the idle screw and then use a small screwdriver into the carb intake to lift the slide. if you cant keep the engine running then you have a issue as most even if rich/weak will idle if slightly higher. If you can't get it to idle at all then recheck for a air leak.