Carburettor problems

[Ron]

I know this is a problem that's been talked about on the forum before but it's one peculiar to me at the moment, and I can't figure out a solution.
The problem is that the carb (Stromberg 150s on a Vitesse) pistons won't return with that satisfying 'clunk' when they hit the bridge.
With the suction chamber removed they appear to be OK, but then I guess they would as there's nothing to stop them returning to the closed position.
However, still with the carbs dismantled the piston won't fall away from the suction chamber without a little help, it's almost as if the tube inside the piston is fouling the tube that holds the damper when it tries to fall.
Does that make sense? Any ideas?

[Clive]

Have you possibly turned the tps from their original position at all? and have you centralised the jets (assuming strombergs need centralising!)
Apols if you have already done those.

[herald948]

...or could the tops of the carbs gotten swapped at some point?

[Ron]

Thanks for those answers, I'll try swapping the tops and moving them around. They may have been swapped at some point in the past but as I've currently only got one carb apart it can't be that. What baffles me is that the piston sticks in the up position when the carb is apart and I'm just trying it on the suction chamber without anything else being connected.

[nang]

How about a fine wet and dry paper on the bore and /or piston to clean off any accumulated gunk?

[Ron]

Thanks for that, you must be a mind reader. In the end that's what I did to resolve the problem, some 1500 grit wet and dry. Mind you tightening the suction chamber on can make a hell of a difference, that little bit too tight and the piston seizes again. Trial and error with those screws until you get it just right.