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MG MGB Technical - Carb problems

I purchased a 1977 MGB 2 weeks ago. The car idles and runs fine, after the car runs about 5-10 minutes when I come to a complete stop and start off, the car misses and shudders and I have to stay on the clutch to get the RPM's up. In second gear and on this is not noticable.
I have been told that it is the auto-choke. After following some directions I found on the internet I checked and cleaned the autochoke assembly and found nothing abnormal.
My question are: Do I need to replace this with a manual choke? Does the carburator need rebuilt? Could there be anything else causing this problem? Would I be better off to replace the SU carburator with a SU HIFF 44 carburator or something?
I have wondered by the time I finish replacing the choke and rebuilding the carburator- would it be better to replace the entire carburator?
Thank you for your time, Tony Gatewood

Hi Tony.

Yes, it could be something else, but my first move would be to remove the auto choke after checking the carb for obvious wear and misadjustment and replacing the air filter.

Is the throttle spindle loose in it's bearings, ie will the spindle move up and down ?.

What colour are the plugs ?


I do have a little play in the spindle The throttle quadrant( lever where the gas pedal cable attaches. Kentucky mechanics term )was pretty loose and that most likely caused that to wear on that side.I have to give it some good effeort to feel it but its there.
The plugs had some carbon build up on them i cleaned the plugs last week and checked them out.
I had a problem with the car running after i shut it off and installed one of the diodes on the alternator line (you guys all know what i am talking about)is there any way this could had made my problem worse?I am trying to think of the last things i have done.
Thanks for your input.

Send me your email address and I'll send you my "Those Damn Zenith Stromberg" article which will give you the answers to your problems.

Remember that the success of a tuneup lies in following a logical sequence of steps covering four systems: emissions; engine; ignition; carburetion.

Many owners begin fiddling with the carb believing their problems lie there. You'll notice the carb is at the END of my list.

John H Twist

This thread was discussed between 07/08/2005 and 08/08/2005

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