Modern Vespa

Hello to all, I am new to this forum. I am searching for my problem for a while here, but I am not sure i found anything useful, maybe i missed some replies... So thanks in advice to everyone that will help me

I have LXV50 Vespa (engine identical as LX50) and sometimes after 10 days or more i have problem starting it. I contacted my friend that is mechanic and he advised me to check electrical choke - we solve the problem with unscrewing the el. choke, add a little fuel in the hole, put everything back together and it started without problems. Since then i did this everytime i had this problem. But this is not the solution because it is time consuming..

Everything else is perfect till now with my Vespa..

Any advice is appreciated

Thank you!

Nikki

Aloha and welcome to the forum from Hawaii. What year is you LXV? Might be a bad battery. That's where i'd start. If you take short rides it doesn't charge the battery fully. If you don't ride it everyday get a battery tender and put it on it. Your battery will last a lot longer. Good luck.

Hello!

The battery was changed this year and it is fully charged. So this is not the reason. We actually get it to work as I described before, but i want to know why is this happening.

It is 2008 model.

Thank you.

Could be the electronic choke (enricher) is not working properly. There is a test procedure in the workshop manual.

-Craig

I am searching the workshop manual, but can not find the testing procedure. All I found is to replace it if it is damaged.

Thank you for your help!

Amizon has a GY6 carb for under $30.Its the same for lx50 but not sure what's on a lxv50.The shop manual might tell how to check carb choke.
http://www.wotmeworry.org.uk/manuals/useful%20info/Piaggio%20Tech%20Manuals.pdf

http://scootergrisen.dk/scooterhjemmeside/download/vespa_lx_4t_servicemanual.pdf

Found it. Will do the test tomorrow. Thank you!

Is it a 2 stroke or a 4 stroke?

It is 2 stroke engine.

I checked the carb choke according to manual and it does not work like is should. It extends for 1mm only after 5 minutes.

Will replace it and see if this was the problem.

Thanks to all of you for help!

Just got new el. choke. So far so good, it works. I made a few kilometres today and it runs great. Waiting for bad weather to not to touch my vespa for 2 weeks to see if new el. choke solved the problem with starting

If anybody has another idea what was wrong, please write down.

Thank you

Back after few months. So weather get colder and my vespa stayed at garage for a few weeks. Same problem occurred!

Automatic choke works (tested!) and it seems that fuel (from carburattor or inlet pipe from fuel tank) somehow evaporated and it just can not come back until i put a little fuel under automatic choke. Then the engine starts immediately.

It is annoying. I just have to unscrew auto choke and repeat the process every time my vespa stay in garage a few weeks.

Has anybody the same problem? What is actually the problem here?

Thank you!

Where are you located and what year is your Vespa?

Has anyone messed with the carb drain screw? Have you checked for gas in the float bowl? You said the gas might have evaporated after sitting. Might have drained out while it was sitting.

In Slovenia, Europe. The year is 2008 if this helps solving the problem

I bought it as used and it worked until i left it 2 or 3 weeks in garage. Don't know if somebody messed with carb, but it works perfect in idle and when driving at full speed. It just won't start after a few weeks.

Fuel is in the tank and float bowl is pretty dry (like i saw in short time that i had to check).

Isn't it strange that fuel evaporated in only 2 weeks from carb and pipe line?! And why it can't suck the fuel when i try to start it? And when i put a little fuel under auto choke it starts without problems...

The 2008 is carbed, not fuel injected.

Have you checked the fuel tap, vacuum and fuel lines for cracks or pinholes?

Will check tomorrow. So to do it, I should empty the fuel tank and unscrew the fuel tap to check it carefully, right?
How do I know if fuel tap works correctly?

Pull the vacuum line off the inlet end, Pull the fuel line off the carb and place in a container. Suck on the vacuum line and fuel should flow into the container. When you stop sucking it should stop. Check the condition of lines too.

To test your fuel-tap....

1) remove both pipes from the carb
2) check both pipes for splits/cracks/leaks
3) put the end of the thicker fuel supply pipe into a container to catch fuel
4) suck on the slimmer vacuum pipe
5) if it works ok and fuel flows into your container then the fuel-tap is likely to be ok
6) if no fuel flows then replace the fuel-tap

When you stop sucking on the vacuum pipe it should stop, if it doesn't then your fuel tap isn't turning off which would lead to the carb being flooded and it struggling to start.

Fabio

I tested the fuel tap and it works like it should. Checked booth pipes and cleaned them. So this is not the problem.

It is time to open the carb and clean it?

Thank you.

Have you tried giving it two twists of the throttle before trying to start? The accelerator pump should squirt fuel directly into the intake.

Out of interest.....if you start it every day does it start perfectly....but if you only start it once a week or so its then that you're having problems?

If so its maybe because the fuel is evaporating/or backing up/or leaking out of the carb, that's why when you add fuel directly to the carb it then starts straight time, once it has started then there is a strong enough vacuum created by the engine to keep the carb full enough of fuel, but when its dead cold and is starved of any fuel in the carb then it doesn't open the fuel tap sufficiently? To create this sort of vacuum you need a very strong battery that will turn the engine over quickly enough to create the sufficient vacuum to open the tap. These are only my thoughts and they may not be correct here...but hey what do I know?

JimC has recommended 2 twists of the throttle to prime the carb, but I think this only works with 4stroke bikes that have an accelerator pump on the carb. (again I may be wrong here too)

I think you said that your bike is a 2stroke and I personally think that a faulty fuel tap is still the problem.

Dont know about pump, but twisting throttle doesnt work. It has a new and fully charged battery. I tested and when i am trying to start it, the vacuum is there and a lot of fuel came out of pipe. then i put the fuel pipe back to its place but it didnt start.

So what is next?

So I decided to clean the carb. And I did it Although the smaller jet did not seem to be dirty (I cleaned both just to be sure), it did the work, the engine started!

So far so good.. BUT! It seems I moved the idle screw so it died once it get hot.

Here is a pic of my carb. There are two screws, one you can move with fingers, but it is not doing anything. A little help would be appreciated

Thank you!

Ok, so i adjusted the idle speed. Now it seems that i have problem with fuel/air mixture.

Here is a pic of my spark plug (perhaps I need a new one? )

What does this colour mean to you? And which way I have to turn the screw to get less fuel and to which way to get more?

Thank you!