Weber mystery

One for the carb guru's.
I changed the Weber carb on my S3 109 for a new unit a couple of years ago as I could never get to the bottom of the problems with it. Afterwards I put a rebuild kit onto the old carb & put it into storage.
So last week the carb on my wife's 88 starting playing up with broken, bent & generally knackered linkages & springs. So thinks I I'll put my old unit on a see how the rebuild kit went.
Straight off it drove fab, loads more power but then we started to notice the problems I was having with my 109 coming back. Plenty of power at medium & higher revs but spluttering at low revs, smokey exhaust & occasionally running on.
I've checked everything through again & the timing & valves clearances are good. I've even gone as far as comparing the jets between her old carb and my refurbed unit & they're identical. 190 air & 165 main.
Be very grateful for any advice or pointers please & thanks for reading through my waffling.

Same unit causing the same problem as before, hmm. Try reducing the level in the float chamber a tad.

Seal on the butterfly shaft

J

marjon said:

Seal on the butterfly shaft

J

Click to expand...

I always suspected an air leak when it was on my truck. The rebuild kit included a bunch of O rings and 2 seals for the butterfly shaft. Tbh I wasn't convinced they were very effective at all but fitted them anyway.
It's an annoying issue as it doesn't really make sense, probably going to end up with a new carb.