Modern Vespa

Morning CMan
I've tinkered and adjusted the mixture screw in and out. 1/8th turn this way and that. I've got her so she's ok but your thoughts on getting a new set of jets has got me thinking.

If I bought a new Dellorto Carb for £90 it would have every new jet and I presume the mixture screw would be preset on this?
Also new float needle, fuel filters etc.
For £90 it sounds like a no brained.
I was looking at this one.
Any thoughts welcome

https://beedspeed.com/products/vespa-genuine-carburettor-standard-20-20mm-px125-150-auto-lube-eng?_pos=1&_sid=7e0ba335d&_ss=r&_gl=1*1orp6ir*_up*MQ..&gclid=Cj0KCQjwi5q3BhCiARIsAJCfuZmrhZ3v6pCKlUgQMqSIKAcRihPjsmFt2WgS3LeqEYqSeCmyLGjiiUcaAjagEALw_wcB

There's multiple ways to think about this, but that's no guarantee it will be any better. If it were, this sub-forum would have about 40% fewer posts than it does.

The issue is not that jets wear out, though carbs sometimes do. It takes a lot of wear for a carb to wear out, though.

More likely, your stock bike has some other issue that you're hoping will resolve itself by bolting on a new carb, but that's not how these things play out.

For the time being, if it's running reasonably well, I'd just ride it until either your riding season ends or it develops new symptoms that we can diagnose over the Internet.

Also, what'd you find out about the exhaust? Is it catalyzed or not?

To save buying a new carb; Easiest way that there is to adjust the mixture screw.

With the engine already fully warm but off. Gently turn the mixture screw in until it stops. How many turns was that? Remember it.

Undo the screw 6 whole turns, if it's a scooter you don't know well.

Start the engine.

Turn the idle adjustment screw all the way in until it stops.

If normal it will be a fast idle but not running way high.

Adjust the mixture screw in slowly until the rpm speeds up. This will happen suddenly, from smoky and lumpy, to faster and smoother, within half a turn. Stop there. If you keep adjusting in it will get lean, high rpm fast and incorrect.

Undo the idle screw to a reasonable idle. I like 800rpm (slow where the headlight flickers) because the cruciform lasts longer.

Check as the throttle is suddenly opened a small amount, the rpm just increases clean with no fuss.

On a modern SI carb, with the correct pilot jet small number, the mixture screw will now be 2.5 turns out.

Biggest wear part in these carbs is the (black) float needle tip, especially if you're running fuel with ethanol and don't run the carb dry before storing.

You can test the seal by leaving the fuel tap on for a few hours. If it's leaking the engine will be flooded and not want to start without a lot of work.
If so, try a spring-loaded Viton (orange) tipped needle. Easy to switch out.

Loads of great advice on here. Thanks fellas. Lots to look at and think about.
C Man, I checked the exhaust and think it's catalysed, I took a picture please see attached. Is that the catalyser?

The carb I have is a SPACO
I closed the mixture screw all of the way and then turned it out 2 full turns.
It works, it runs, runs really well at high speeds, now the idle jet is clear it does pick up well. But I still get the ' missing a beat' issue

It is the factory fitted that came with the scooter. I bought it as new in 2015

Definitely a catalytic convertor

You got the upgraded model, you go the Flux Catalyser.