idle unsteady

[the-urban-spaceman 1]

Hi all,

Does anyone know how to cure this? When pulling up and dropping clutch revs stay at 1200 for a bit before dropping down to normal tickover. Remember 30 years ago a carburettor place told me they put a thin piece of metal somewhere to take up the slack, but not sure where or how to get to it. any ideas?

[sheffieldcortinacentre 765]

Hmm I'd say as the throttle doesn't appear to be twisting, that the hole that  throttle spindle ( number 12)passes through body of carb has worn oval allowing a momentary air leak.

Try a squirt of WD-40 or similar & see if revs drop as the liquid seals the leak.

[sierra3dr 53]

Has it always done it,or is it a recent occurrence?

[WS1 13]

I agree with Craig, that looks like its got a leak into the carb thus changing the mix ratio, spray easy start around the carb and if the revs raise then youve found the leak..... on the metal strip, ive not heard that but the newer (rubbish) webers instead of a bush they use a teflon strip wrapped around that spindle on some carb models (im told)..... found this out when i purchased a brand new carb and there was a leak... the seller said thats the best i can do, it went back!!!.

I then had an interesting conversation with a carb rebuilder that confirmed the above and that he 'rebushes' them so they dont leak.... because i was desperate i purchased a chineese carb off ebay for £80 and it is far better than the new weber.... I will however be having my old carb rebuilt at some point because i dont feel the chineese one will last.

[the-urban-spaceman 1]

On 7/12/2025 at 6:49 AM, sierra3dr said:

Has it always done it,or is it a recent occurrence?

did it years ago. carb place padded it out with something, not sure where.