Modern Vespa

Hi guys I have a 2000 et4 pre leader engine when I start the bike I got to keep throttle on as soon as I let go it cuts out I have cleaned carb and air filter new spark plug what else could it be now it won't start 😭😭😭😭

Check for an air leak on the intake side of the engine. Look for a loose or cracked vacuum line or a crack in the rubber intake manifold.

When you cleaned the carb, was it a complete disassembly? Did you remove the jets and clean them thoroughly? Did you let the carb body soak in carb cleaner for a day or two to dissolve any deposits in the internal passageways?

-Craig

Idle screw could also be the culprit. I've been looking on this forum for the "default" number of turns out but it seems somewhere between 1.5 and 3, that's from the starting position of screwing the idle screw in all the way.

Thanks guys will have a look for splits and check screw as well