Modern Vespa

Battery full,oil/petrol full,cleaned the carb ,checkes the hoses,but each time I turn on the ignition dieswithin 5 seconds,if I try to pish the throtle it dies instantly.Any ideas?

fuel - air mixture may be the problem. Too rich I guess.

check if the valve in the tank(petcock) opens and gets vacuum from the carb

All working.Cleaned the carb,checked vacuum,all fine,no whispers,air leaks.I even changed the spark plug,same simptome.It just dies as soon as it starts

Can you post a video of it?

Hi!

I actually have the same problem. Starts and dies. After it gets warm it will run on idle, but as soon as it gets resistance, it dies out to idle or even stops.

Cleaned carb, vacuum hoses are good, new manifold, new vacuum petrol valve, new spark plug. Gas is flowing generously to the carb. Auto choke working (maybe unsure of how deep it should be set?). Vacuum membrane is ok.

It runs "ok" with half throttle downhill, but as soon as I start uphill, it looses all power.

See video.

https://www.dropbox.com/scl/fi/bcod3yj0npu025dj9lti2/Video-21.05.2024-22-26-24.mov?rlkey=4pm9y0iggu0i2chmoj8rpua9z&dl=0

KaiNorway yap,same with mine.But at least yours is working for a few moments.Yours might be a issue of fuel/air mixture tah can be solved from the valve

wbdvt please see attached link of the video
https://youtube.com/shorts/iriywWwN2CA?si=88hvP6MCchxF8Nyr

I received the verdict from Vespa mechanics yesterday: No/low compression on engine. Valves or top needs to be machined or even changed.

🤬

Went with mine at the mechanic as well.Faulty valve,changed it

Faulty valve, like in the top or petcock valve?

Just an update on my issue. Adjusted valves, and it seems to be running good now. Will have an endurance test later this week to see if it is really fixed.