MG Car Repair: mg midget 1500 su carbs, swirl pots, butterfly valve

Question
Hello,
I'm trying to identify the location of the idle screws on my (HS4?) twin carburetor, UK midget 1500cc.  The manual shows it close to the dashpot bowl in a vertical position as a screw with an exposed spring around it.  All I can see in that area is a cross head screw recessed in a part of the casting and with no visible spring around it.  There is one for both carbs and these are on the 'inside' ie inbetween the carb bodies with the swirl pots being on the 'outside'.  Is this the right screw?  Also is a carb rebuild using a kit of parts something a reasonably mechanically competent person can do or is it best left to an expert?

Answer
Hi Richard.  My book shows the same as yours.  Your UK car should have twin HS4 carbs, either AUD328 or FZX1122 depending on the year.  I have seen such a cross-head screw used on some SU carbs but never on a UK 1500 Midget.  On some USA cars the screws were recessed into the casting and the heads covered over with small metal bungs to make them tamper-proof.  

You could check by screwing one of them in (clockwise) a full turn.  Does it start to open the butterfly valve?  If so, you have found it.  Don't forget to turn it back again.

Yes, carb rebuilds are fairly straightforward.  Buy a rebuild kit from Burlen Services of Salisbury.