Modern Vespa

After 4 months, I went to start my Vespa gts 300 and the starter motor is always on.. (always try to start the engine, while the engine is running)

Any suggestions?

It's probably a stuck starter relay.

FTFY` This is not an uncommon fault. Each time the relay breaks the starter motor circuit, there's an arc across the contacts. Eventually this welds the two contacts together.

A quenching diode would suppress this, but it's not *that* common a fault to justify the factory adding one.

Cheap and easy enough to replace.

I once had a Burgman that had a faulty start switch that kept the starter running, but only when the ignition was on.
BTW Jim, where is the starter relay located on a GTS 300?

It can't happen on any Piaggio bike as a brake lever has to be pulled as well - now if a brake switch was faulty and on AND the starter button was faulty and on, then, OK, it would be those at fault instead. The likelihood of that is absolutely tiny though. On the RH side frame, underneath the petcarrier.

I probably was at a stop with the brakes applied when I noticed the headlight was dim or off. I then figured out that the starter was running, and traced that to the start switch.

Thanks for the location of the relay. I'm sure that will help the OP and others.

JKJ-FZ6 wrote:
(It's definitely a stuck starter relay)

Thanks for the help.

So I need to change the relay and install a diode?

Yes, change the relay. There may be such a thing as a starter relay with a built-in diode, I don't know. If not, I personally wouldn't worry too much about it.

Don't worry about the diode - just put a new relay in.

Thanks very much for your help. I will change the relay

Where is the starter relay?

I'm sorry you took everything apart, but you can easily spot the starter relay once you lift open your seat and remove the pet carrier...

It's the red squarish part near the opening. You can't miss it.

Thanks very much…. It was very easy… and now everything is ok… 👌👍