I have a 2.1 engine and an SU carb that does not like cold weather.
It startsok when cold - maybe cranks a little longer than normal - , but takes a loooooonnnnnngggg time before it will take any throttle. No matter were I set the choke it acts the same. When the engine is at operating temp, it's better, but still hesitates under load.
I should perhaps mention it is a 1976 engine (formerly injected) and I'm not quite sure what year the carb is.
It is also rather gutless, compared to my 84 2.3.

Anyone have any ideas on what the issues could be?

Thanks.

 

Gees! It's been many years since I've worked on an SU. The last carberated Volvo I owned was a 68 122S. They're pretty simple, though. Rejetting is pretty much standard for the course and doesn't cost a lot. Likewise, float chamber rebuild which should be adjacent to the dash pot.

On the old B18 the SU's were really simple to adjust. Wind in the jet adjustment all the way and back it up by six flats. I have no idea what you have, but if it's like the old SUs, there's not much to them.