Modern Vespa

hello how's everyone doing im new here. im having an issue with my vespa about 2 weeks ago I took off the speedometer to replace the battery for the time clock on my vespa gt 200. when I did the gas gauge needle had fallen off I did not think much but to put it back on to the Empty line. rode it for 40 miles and noticed my gas gauge was stuck on the full level I took gas out and still stuck all the way at the top on the F mark. when I turn the key the needle goes up to full and when I turn off the vespa and turn the key off the needle goes down and it should. can anyone give me a few tips to try or what I could do to fix this thanks everyone.

Well, first, the lack of punctuation makes this tough to read.😉

But, can you access the fuel tank float? Open the speedo again. Remove the float and manually make the needle move.
I just did that with a Non-Vespa.. to test the various elec bits.
Fuel not needed. Turn on the key..gently raise the float… see how the needle responds.
Just a thought.

Access to the float is the stumbling block.

I expect there's a bad connection to the headset from the sender.

There's a pin it rests on at empty? Probably with the scooter off it drops way below that so you need to recalibrate.

Fill the tank.
Pull the needle off with the scooter on.
Put the needle on pointing to full.

Thank you for your reply. I tried that and still no luck.

I have a GT that reads full all the time. Motovista suggested that it was probably a bad sending unit so I bought a new one but because of other priorities I haven't installed it yet.

I haven't looked at the service manual yet. Is it as hard to change as the GTS sender/pump unit?

Luckily the low fuel light is working and I carry a gallon of gas in the pet carrier. If it had a trip meter that would be great but it doesn't.