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MG Car Repair/stromberg carb adjustment


I have a 1977 midget 1500 and I'm having trouble getting the idle down. The choke and idle screw are all at minimum adjustment but it still runs around 2000 RPMs once it warms up good. Is this a problem that I need a S353 adjustment tool to fix? If so, where can I get one. Having trouble trying to find one.
Do I have any other options?

Hi Larry.  The Stromberg tool is only needed in order to adjust the mixture setting.  I do not think you need one, because your problem is adjusting the tickover, not the mixture.  

It should be possible to set the tickover so slow that the engine will not run, so if you cannot get it to idle below 2,000 rpm then you have a different problem.  

It could be that the accelerator cable is sticking, preventing the throttle from closing.  It may be that the cable needs to be adjusted so there is a little free play.

My second guess is that the throttle butterfly is not closing properly because the butterfly disc has not been correctly centered in its hole.  (This often happens if someone has messed with the clamp screws). The butterfly has two small clamp screws which should be slackened but not removed.  The heads of these screws are on the wrong side of the butterfly, so you will need to remove the carb to do this job.  With the two throttle adjusting screws adjusted so the butterfly can close, operate the butterfly gently so that the disc centers in its hole, then tighten the two clamp screws.  Looking through the inlet you should NOT be able to see any daylight around the edge of the butterfly.    

You should now be able to open the throttle on the adjusting screw until the car to runs properly and then set the choke adjusting screw.

If these fixes don't work, get back to me because there are a few other possible causes, but they are less likely.

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Barrie Jones


MG Sports Cars from 1949 to 1980 - Including MGB, MGBGT V8, TF1500, TF, TD and modern Midgets. I also specialise in SU carburettors, Lucas wiring, suspension, steering & brakes.


I have owned my 1955 TF1500 since 1966. Technical specialist for the TD and TF with the MG Car Club T Register. Also owned 20 MGBs and currently own an MGBGT V8. Written 3 books on MGs and produced a DVD on how to strip and rebuild the TD/TF gearbox.

MG Car Club.

Barrie's Notes on the 1953-55 MG TF (author). /=====/ Barrie's Notes on the MGB (author). /=====/ Barrie's Notes on the MGB GT V8 (author). /=====/ The Essential Buyer's Guide to the MG TD, TF and TF1500. (author)

M Phil, C Eng, BSc (Eng).

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