Modern Vespa

On a recent trip my Vespa LX 125 (2005) started coughing and spluttering. When stopped it was very difficult to start again and would barely run only on full throttle. I put this down to having filled with old fuel. I also had issues with a petrol strimmer that used the same. The strimmer is working fine again having drained the fuel, cleaned the carb and used new fuel.

On the Vespa I have also drained the fuel, changed the fuel tap and filter and refilled with new fuel but still runs rough. What else can I do? Clean the carb, replace parts in the carb? Is there a carb repair kit available? Grateful for any suggestions.

Your scooter is 19 years old. Check for air leaks. Replace all the fuel and vacuum lines if they are original. Be sure you don't have a crack in the intake manifold. Do this and see how it runs before you yank the carb.

Thanks.OK will do. Just seems strange that other engines using same fuel had issues. Is there a problem with dismantling carb?

No.
It's the reassembly that causes problems.

OK thanks - can you point me to any guides, videos that would help in case I have to do it. Might try adjusting mixture before that. Will check everything else first.