Modern Vespa

Hi Guys,

Searched high and low in the threads and on the internet for a solution to this one. Backstory....

Long story short... a painter decided to do some unsolicited service to my Vespa. I told him not to, but he hooked up a massive 4ft tall Industrial battery charge to my battery to boost it... (i heard a pop) and then he also opened up the carb and then didn't put it back together properly.

I finally got the carb seated properly (at least I think it is) and now the Vespa won't go faster than 60 km/h. (~25 mph)

I've checked the variator/rollers/belt and anything else it could be... there is just no power and it's super sluggish maxing out at 50-60 KM/h.

Any idea whether this is just that Carb issue where you think it's seated but it's not... or if there is something more serious at work with the ECU being fried from the charger?

Vespa is very low mileage and has me stumped on what else it could be.

Hoping for some help from the legends on here!

Just to follow up here.

I've read numerous posts, noting greasy125 's feedback about making sure the diaphragm is 1000% seated.

It seems like it is... but I've seen that even if you think it is... it's not.

I'm going to manually remove it and check the operation with compressed air.... but before I do that, would love to verify that the ECU affects the advance timing in someway and perhaps that's why I'm getting sluggish performance and/or a complete lack of power. A motorcycle mechanic I have a lot of trust and experience with suggested this might be the case.

Also worth noting that the engine sat with old gas in it for a while. I put in some Seafoam and ran it through a full tank of fresh gas. Tried a different spring. Cleaned the carb. Checked the plugs...

I'm really at a loss here... Is it common for the ECU to pop when being charged by a heavy charging device? Or is this most likely still a carb issue?

Assuming the huge charging device was a 12V one it should have been no problem - it's the voltage (and polarity!) that's important, NOT the current delivery capability.

Thanks for that. I always assumed it would draw the current it needs... regardless of how much it can supply.

I can't be 100% certain but the unit he used looked something like this,
Which does have a 24V mode. I did hear a pop, but that could have just been the battery arcing as it connected.

Set the diaphragm with silicone grease and be sure it is 100% in place before you do anything else.

That's the next step for sure.

WOW!

It totally worked! The power is back. I did notice that I do have some slight backfiring now... usually after I lay off the gas.
I also noticed a white film/residue on the diaphragm. Cleaned that off too and it seemed better.

I was really laying into the accelerator to test the power and speed, and when I let off I could hear a slight pop coming from the exhaust.

I wonder if I might have left a bit too much silicone grease out of the groove.

Thank you so much for the tip. Saved me a ton of effort!

The backfire is usually an exhaust leak. Put the scooter on the center stand, start it up and plug the end of the exhaust with a towel. If it doesn't die, you have an exhaust leak.

Will do. Thank You!
Trying that in the next couple of days.
This is a new issue and I'd never had it before any of these carb issues occured. I'd be suprised if it ends up being an exhaust leak... but surprises ARE common it seems for me and this Vespa Journey!