Modern Vespa

Hey folks! I've been having this issue for the last few months and haven't been able to figure out the cause. My 2013 S50 seems to hesitate/lose acceleration whenever I use the turn signal while accelerating. This is most noticeable when I'm going over 30 mph or so - I can't recall it ever happening while in stop-and-go traffic. I also noticed that the instrument panel light sometimes pulses when I'm stopped at a light with the turn signal on. So far, I've cleaned the carburetor & jets, replaced the float gasket in the carb, replaced the fuel line, checked all hoses for leaks/cracks (none), changed the air filter and replaced the spark plug. I asked the local vespa mechanic about this issue and he had never experienced this before, but Vespa wants to charge $130 just to run a diagnostic (not even including repair), so I'm hoping this is something I can fix myself.

Not sure if this would affect it, but I noticed when I removed the carburetor that it looked like the previous owner had cut the wires that connect the carburetor heater to the electrical system. Could this contribute to this issue perhaps? Any other thoughts? Any insight is super appreciated

Of all the things you did to your scoot none related to the electrical system where the problem apparently lies. How about the turn signal flasher or switch? How old is the battery?

What scooter and what year?

Where are you located?

The turn signal pulses are generated in the voltage regulator - and have given trouble to quite a few people. The simple answer is to cut the wire from the regulator, and add a two-terminal motorcycle flasher relay instead.

https://www.scooterwest.com/turn-signal-flasher-vespa-super-300-vespa-s-gts-300-not-250-640289.html

Correct. When the problem initially started, I thought it was normal engine hesitation, which is why I first focused on the carb/fuel/air system, not electrical. It wasn't until after I'd done everything previously mentioned that the problem continued and I noticed the connection with the turn signal.

It's a 2013 S50 4T. Battery is at least 4 years old (last time I took it in to be serviced last summer, they tested the battery and said it was good). I'm located in Miami.

Thank you! Gonna look into this asap!

I think it wouldn't hurt to test the battery again.

these golden nuggets of wisdom...

Agreed 100%. Going to test it today

Right?? So grateful for the community on here

Finally a positive update on this situation (pardon the delay, took a while to finally resolve this)...

After replacing the carburetor and intake manifold, as well as all hoses and pretty much everything related to the fuel intake (at the recommendation of a few local Vespa mechanics), and testing the coil and battery as well (both were fine), the problem with the engine bogging persisted - and still the same problem when I used the turn signal/horn. It idled fine at start-up, but often it just wouldn't accelerate, other times it would accelerate, but then randomly stop accelerating in mid-ride - which is a recipe for an early grave if you're riding in Miami like I am . At this point, I'd done everything I could to fix the problem to the best of my ability and the local Vespa mechanic had run out of ideas of what the problem could be, and thought maybe the valves might need to be adjusted (which of course, would be a pricey fix).

So, seeing no other options, yesterday I bit the bullet and took it to the mechanic to check the valves. After multiple attempts, I was able to get it accelerating, but about 1/4 of the way to the mechanic, it just shut down and wouldn't restart. So I pulled over and sat for a moment to ponder the meaning of life. When I finished pondering, I went to restart it and noticed that unless I turned the key all the way to the right and held it, the engine wouldn't turn over. Ok... strange, but noted. So I pull back onto the road and proceed to ride over some bumpy train tracks and the engine starts bogging again and, rather than pull over, intuition told me to turn the key all the way to the right and hold it again... and, surprisingly, as I did this the acceleration kicked back in and I was able to eventually make it to the mechanic (riding one-handed... all while holding the key ).

So after 4 months of trying nearly everything... and dropping an unnecessary $300+ and basically rebuilding the entire engine, it ended up being a bad ignition switch that caused all of those other issues lol. Literally a $17 part (the mechanic was a stand-up guy and just charged me for the part - no extra for labor since it only took him 10 minutes to fix). He admitted that he probably never would have figured out the problem if I hadn't made that discovery on the way there.

Since I have never seen this specific issue on any other posts/forums, I hope this helps somebody else going through the same problem.

Thank you all for your input!

Blimey - I had issues with mine, but it didn't cut power. I just had intermittent starting issues, so I had to wiggle the key to get it going.

Suppose it depends on which contact(s) get corroded.

"If you can't fix it with a hammer, its an electrical problem."

Absolutely. Also, because I'm surrounded by salty ocean air here, things corrode here VERY quickly. That said, now that it's running great, is 10 years old and has 15k miles, I'm strongly considering just selling it and buying something newer since more corrosion-related problems at this age are inevitable

nope

Glad to hear you've sorted it!

Just to say that adjusting the valves is sometimes financially worthwhile. My fuel economy has massively improved after having the valves adjusted at the first 620 mile service.