I have a 1600 with dual 32-PDSIT carbs.
No matter what I do it seems to always run rich...timing is set ok
I find though that the mixture screws do bugger all...one I can screw right in and it makes no difference.
Always pops out the exhaust when backing off and even runs on sometimes...smells fuelly too.
I've checked for air leaks and replaced all the balance pipes between the carbs. Carbs also have had kits in them.
I did notice there was a small amount of side play on the shafts although it doesn't seem excessive.

Any ideas ?

All in all, all the symptons of running rich.

Just my thoughts but if the mixture screws do nothing then they may be dirty you will need to take them out and clean them and where the go in the carby

Marc

the seals on the screws may be perished. Check them aswell. That was the case with our carbs. We couldnt b botherd to go an buy a O ring for $1 so we just used some heat shrink. Made a huge difference in the tuning of the engine. Good luck with it.

Does it run rich at any particular rev range? Maybe try to find that out first.
If you have checked the suggestions above with no effect you may need to look at float level, does the fuel inlet valve leak?
Also check idle/main jet/air mixture screw sizes. Many carbs have been altered over the years, and can be a mess by the time you get them.

Thanks people...might rip them out on the weekend and have a look.