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MG MGA - Throttle adjustment

I have a problem with idle. OK when cold 500 rpm
When hot it rises to 1500+ which makes gear changing and slow driving rough. On inspection, the cable feels a bit tight, ie very little if any slack. Its a night mare trying to get to the cable clamp. I'm looking at where the operating lever is fixed to the carb shaft.
Is this a fixed position or if I slacken the clamp, can the lever be adjusted finely on the shaft?
Art Pearse


Hi Art

This is the easy way, use cable adjusters from a bike. Tighten the clamp with some slack and do fine tuning with the adjuster.

Cheers
Dave

Bolney Coupe


As always, the picture gets inverted.
Bolney Coupe

Hi Bolney. Good idea. Where did you insert it?
I managed to get the cable clamp loosened and I now have 1/8" free cable at rest. So pretty sure the 6202827241003002cable itself is not causing the problem.
Started the motor and Checked that only the rear carb stop was active. Set to 500 rpm. Let it warm up without touching it and idle rose to 1000 about. Reset to 500
Then did a bit of throttle blipping. It returns nicely to 1000 but then only very slowly to 500
Checked for air leaks with lube oil squirted round the carb shafts - passed.
Next step is to release the shaft connector and get them equalized.
The throttle return spring is very strong. I'm wondering if it is needed, with each carb having its own return spring. What do you think ?
Art Pearse

Could be idling a touch on the lean side --if it is that causes an unstable idle speed hot.
William Revit


Hi Art

The setup shown is for an 18V with MGB heat shield. I don’t have an MGA heat shield to compare but the adjuster would go into the MGA abutment where your current throttle cable end goes.

Also an assortment of useful bits scrounged from bikes, mowers etc.

An added advantage is that the throttle cable is raised, preventing chafing on the rocker cover.

Cheers
Dave




Bolney Coupe

This thread was discussed between 26/07/2026 and 28/07/2026

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