Modern Vespa

My 2009 gts 250 cuts out whenever I go over bridges or something wide open that is uphill. I already had my voltage regulator replaced, so I know its not that. Anyone have a clue what is causing my engine to cut out?

Can you give us a bit more information?

So it cuts out and then what? Do you have to wait some time before it restarts? Or do you have to push it home? If you get it restarted, can you then just finish the uphill part?

When does it cut out? Immediately when you get to the uphill part, or after some time?

What do you experience immediately before cut out? Everything normal and then suddenly the cut out? Or do you feel there is loss in power and then cut out?

It cuts out about 200-300 yards after starting on the bridge. Usually I hear the engine starting to struggle and it will stay on but the throttle won't do anything. And it seems like the engine is gasping. The engine won't cut out right away and it slowly dies out. It then won't restart right away but i'll have to wait about 1-5 minutes to get it restarted. I can usually get it restarted after a few minutes but sometimes i'll have to push it back for a while.

The symptoms sound a bit like fuel starvation, but I'm at a loss to explain exactly how.

I can also imagine a few other possible (but mostly improbable) scenarios. One very remote possibility, for instance, could be that the electrolyte in the battery is low, and some of the plates in the battery are becoming exposed with the upward angle of the bike, which then leads to power degradation. But the stator would probably also have to be marginal for this to be a likely scenario, so... like I said, mostly improbable.

Where on the planet are you located (not a strange question), When was the last time you changed the Fuel filter and at least cleaned and re oiled the air filter, If its a long time make a start there as Jess says fuel starvation on Incline then recovers then dies scenario, long shot fuel pump clogging but if its okay on level ground I would look at fuel filter first. 😉👍

May also want to mention how many km or miles on that 15 year old bike.

Scooter had about 15k mile on it. Located in a city east coast. I havent had major work done on bike in a while. I had it serviced not that long ago in terms of miles but i'm not sure if the filters were changed.

I'm guessing Sydney as that has a famous bridge and is on the east coast

Scooter likes to stop and look at the view.

Its nyc.

I haven't changed the battery in 5 years so i'm going to try that but i'm not sure why battery would fail on hills.

Which bridge, or perhaps better, what sort of bridge? Is it just inclines (in which case what about any other hills thereabouts?) or is it metal grids (vibration?) or what?

I don't know that this is it, I was just trying to imagine the things that could be affected by the inclination. If the battery is a standard lead-acid wet-cell battery, then maybe a low electrolyte level could expose the lead plates to air when the bike is on an incline. maybe.

It's not very likely, though.

Sticking variator - transmission is stuck in high gear and the engine is bogging on the incline

Weak fuel pump or clogged filter in the tank

Low oil - engine is seizing when the incline changes the oil level and the oil pickup sucks air

Man, what you taking

So the list of culprits are fuel injector, fuel filter or something with the oil.

There are a lot of possibilities, actually -- anything related to liquids. None of them are a slam-dunk, though, and some of them are possible but exceedingly unlikely. For instance, you could have a buildup of oil in your air box that blocks the flow of air to the engine when you're on an incline. Possible? Yes. Likely? No.

This is a really fascinating problem, but I fear you're going to have to do a lot of diagnosis to pin it down. Do you have a convenient non-bridge hill you can replicate the problem on?

Or it's afraid of the troll under the bridge.

Every now and then it also happens if i'm on the highway as well without an incline. I'll try to take the speed up on open road to see if I can get it to cuts out that way or not. If it cuts out at highspeed on flat surface is it more likely an air filter issue?

I genuinely don't know. It could be almost anything at this point.

Just remember when you are on an Incline or accelerating on a highway the engine is demanding more fuel and air, If its not receiving it then it will labor/stall.
I would start back at the tank, pull the line with the aid of a jug check the flow then same with pump and filter if you are not sure how long the filter has been in line swop it out (good practice) then check you have good flow up to the carb.

same with the air filter Clean the filter with brake cleaner/petrol, dry re-oil with filter oil then follow it through into engine compartment checking for splits/cracks loose clips making sure everything is sound.

If you are not sure the workshop manuals with diagrams are available on here.

Thanks. What do you mean pull the line with aid of a jug?

Also, any chance that it is spark plug cover hose?

Sorry I meant pull the fuel line off at the tank to make sure fuel is free flowing from the tank in to a jug not all over the floor.

As for the plug once you have done the fuel and air check, assuming the plug was changed on the last service crank the engine over, pull the plug check if wet I.e fuel present place on cylinder head and re crank if sparking fine then HT lead and cap is fine, replace go for a ride test up an Incline and see what happens.

Thanks. I recently changed spark plug but not the spark switch plug hose/cover. Attached is audio from vespa dying out. It starts to die out around 1 minute into the audio.

Listening to that I'm still thinking fuel starvation, If you do the checks I've mentioned, the only other thing I could suggest Is removing the carburetor stripping it and giving it a good clean and I mean a good clean all the little nooks and crannies everything and making sure the float is free moving and diaphragm is intact and not perished.

Thank you. I appreciate all the help. Which pump and filter are you referring to? Oil filter or a different filter? And which pump? Thanks again

Fuel pump to make sure its pumping and new fuel filter making sure it go's in the right way around.

No carb on the fuel injected 250.

Was that a cross over Jim 2009?.
I have a same age GTV with carb or the difference between a European and USA models 👍

Just a sidenote, heard a case when car engene stopped always on same place. Repair-shop guy had to go a and check the place. There was power lines crossing over road. So, back to shop and tin-foiled the cars ecu...

I was still living in the UK at that time - I never saw a carb'd GTS, but plenty of F.I. ones, and owned one for a while. So interesting! I know my X9 250 was carb'd, and the engines were otherwise pretty identical, so we need the OP to confirm.

A couple of other possible culprits...check the spark plug connection at the boot. These sometimes get a bit tired and need to be replaced.

Also check to make sure you don't have leaks in vacuum lines.

two bricks and a plank of wood as a ramp under the front wheel. Does it start and run?

There has never been a carb'd GTS (or GTV) available in the USA.

And my GTS250 was a '59 plate (first registered between Sep 1st 2009 and Feb 28th 2010). I bought it from DougL, Ivana Tinkle rode it to both Greece and Italy and eventually I sold it to genie. Definitely F.I.

However I can quite belive the early GTV250s were carb'd - Piaggio had to use up the 250 engine parts on something!

The GTS and GTV -- including all 250cc models -- were always fuel injected. In the US. I know nothing of what other countries got.

As the US production runs are always after the EU production has been in full swing, I can quite see the first EU GTV250's being carb'd, but by the time the first US ones were produced they had been F.I. for some time.

The odds are that the carbed GTV was a 125, which we never had here in the US. I'm not aware of any carbed 250 other than the BV and the early Aprilia Scarabeo. The GTV came after the GT60, and they were also Efi bikes.

Make sure the spark plug cap is clicking onto the top of the plug, and that the plug hasn't broken somehow.

Does the bike do this no matter how full the tank is?

Yes, it does this no matter how full the tank is. Going to repace the fuel injector, oil/oil filter, air filter and spark plug boot. And then i'll see what happens. Don't want to give up on this vespa… yet

When it stalls, does it restart immediately or cranks a bit before starting
If starts immediately start checking HT lead/coil/Immobilizer & wiring harness at the bend before it enters the battery compartment. Cranks a bit then check fuel delivery.