Modern Vespa

My 2012 lx150 starts and runs fine, but whenever I let go of the throttle, the engine stalls, and the red oil light comes on.
This situation usually only occurs when approaching traffic or a red light, and luckily I can just hit the ignition again and it starts right up, no issues or anything.

If I want to sit at the light, I have to hold the throttle along with the brakes in order to prevent the stall.

When starting up the Vespa without throttle it runs for a solid 10 seconds or so, sputters slowly then cuts out.

I tested the battery a couple days ago, it was old, so I replaced it, still the same issue occurs.

It's Fuel Injected, so no air/fuel mix or idle screw.

Any thoughts?
Any one ever have this issue?


Thanks in advance,

I'm hearing more and more issues with the FI bikes and issues like this- I would suspect a clogged injector (particularly if you're having top speed reduction) and gas contamination. If it was me, I'd put a shot glass of seafoam in the gas tank and go about the ECU reset procedure.

Blip
Thanks for the prompt response.
The research I've come across during the past week has also pointed to the clogged injector and a variety of other possibilities.

I will definitely give the seafoam a shot first, see if that does it, if not, then clean the air filters.

I'm not familiar with how to reset the ECU though. Is that something only a mechanic could handle?

I will of course post results as I go.

If you can't get seafoam, there's old grampappy skeeter's snake oil and liniment that will completely fix your bike even betterer. You can also gargle with it for gnarly mouth or rub it on your elbows to cure whoop joint.

You can turn up the idle on a fuel injected bike. For some reason US dealers try to do everything but that to fix problems like yours, and you can go down a well that involves a lot of money. The air filter won't be an issue unless your bike ate it, and then it's getting too much air. If you open it up and the foam filter is missing chunks or completely eaten, get a Malossi air filter. They are indigestible. Cleaning the injector also might help, especially if you've ever gotten water in the gas and it sat in the injector over the winter. Usually running through a tank of one of the top tier gasolines will do just as much to clean out the injector, if you let the engine warm up and run it for about an hour.

After you've done everything that is recommended to you, if it still stalls, have someone turn up the idle.

I had a similar problem a couple of years back. Ended up resolving with a valve adjustment. How many miles do you have, and when were the valves last checked?

That's the suggestion that makes the most sense. If the exhaust valves are tight, as the bike warms up, it usually stops idling.
Still check to see if you still have an air filter.

C foam you say???

Try this at home... scrape some carbon out of a tail pipe. Put in a plastic container or bowl. Pour C foam on it and let it sit a few days.
Does C foam dissolve carbon? Report back!

I can't believe it took me forever to realize this, but to fix my "stall during idle," problem, I simply adjusted the throttle cable.
Because I have a fuel injected engine, I knew the Idle Screw did not exist for my Vespa. I thought I was pretty much stuck or not getting to the problem.
I tried checking the oil, I got a new battery, checked the spark plug and electrical lines, ran some seafoam through the tank, and I finally decided to clean my air filter, thinking it wasn't drawing enough air when the RPM dropped.
Though the filter was soaked in oil, it ended up not being the issue.
I finally observed that my rear wheel didn't spin at all when I started up the Vespa, (as it should in idle... just a little). So, over a handful of starts, I would adjust the throttle cable near the engine until it sat in idle, and the rear tire slowly rotated at a constant speed.
That was it!
Not only does it not stall at idle, but the Vespa is even zippier now, and the throttle has very little free play.
I now love hearing that low rumble when I sit at a stop. I didn't think I would miss it as much as I have.

I hope this will help anyone who visits this thread, but if there's any further questions, feel free to let me know!

That's not a fix - that's a work around. You still have a problem.

Did you look for one? It's there.
The problem with the "don't even think about touching it" mentality is that it assumes that ever single throttle body Piaggio ever installed is set perfectly at the factory, and that nothing changes over time.