Modern Vespa

Over the last few weeks my LX50 2T has been flooding when sitting for long periods of time.

So far I've changed the fuel tap and cleaned the carb with no luck.
I thought the float was sticking.
Today I stripped the carb and removed the float needle and seat and cleaned them out. I then put the needle back in the seat and it was really flexible compared to before when it bearly moved.
I then put everything back together and the engine just cranks but doesn't start. Spark is also fine.

Could this be caused by the float being more loose than before or something else like the air filter.

Thanks

I could be, or it could be something else entirely different.

have you confirmed that it's flooding-- currently? like is the plug wet or the cylinder is full of fuel?

the needle can wear, so that may be something to circle back on. the float needs to move freely, but not significantly.

Hi, the engine wouldn't start so I pulled the fuel line and nothing came out, I then I put it back in and sucked on the air tube.
Then after several attempts of trying to start I checked the plug and it was wet.

Also the needle red point looks perfect and not worn down.
Did I insert the needle the wrong way or will I squeeze the part arm on the seat with a pliers?

Could it just be the air filter?

Thanks

With the fuel hose disconnected from the carb, but still connected to the tank petcock, you need to pull the vacuum tube off the carb, apply suction, and confirm that fuel flows readily out of the fuel line. (It does not need to gush out in high volume.)

It doesn't sound like you've done this.

This confirms correct operation of the petcock and the correct connections of the hoses on the petcock. It probably confirms the good condition of the hoses.

If you get a mouthful of fuel then it means the lines got mixed up, and that the petcock vacuum valve is probably not working any more.

Sorry forgot to mention I did actually try that but also it was a brand new fuel tap

Is the carb bowl full of fuel? Test that by disassembling the carb again or by unscrewing the screw that drains the carb.

Still unclear why you attribute the situation to "flooding." No flood conditions have yet been identified!

I will thanks.

If it's not does that mean it's the float seated incorrectly,

If you've confirmed correct vacuum operation and fuel flow up to the carb but no joy in the bowl, then yet, I would start wondering about the needle valve setup. But that would be starvation, not flooding.

If you have fuel pouring into the cylinder and/or backing up into the air filter, THEN you have a flooding issue.

Thanks, I'll check that out.
I just meant as in because the float neddle is loose in the float seat could that cause the no start or fuel starvation

It may be helpful to think carefully about how that needle valve works in operation. Its function is to maintain a consistent level of fuel in the bowl. It's the "load" part of a Class 2 lever system where the fulcrum is the little pin in the end of the "metallic" lever strip, and the "effort" part comes from the float rising in the bowl.

Once the carb is functioning properly and the engine is drawing fuel out of the carb, the needle valve varies from being barely open, letting more fuel trickle in until the float rises and seals it off, to barely closed when the level in the bowl is enough to lift the float and let the needle valve seal. If the scooter is bumping and jostling around that might allow a little more fuel in, but it also makes the float more buoyant and exert more closing pressure on the needle valve. The valve is constantly right on the bare edge between open and closed.

So the answer to your question about if the float valve being loose could cause fuel starvation is "no." If the valve is loose because there is no fuel in the bowl and the float hasn't risen up, the looseness is a symptom of no fuel coming into the carb. If the valve is loose because it isn't sealing properly, the effect will be too much fuel in the carb, not starvation.

If you're absolutely certain you have fuel coming into the carb when vacuum is applied, but no fuel is getting in around the needle valve, then there is a full-on clog in that little bit of the carb (unlikely) or the valve is sealing too tightly. This can happen because old gas adheres the needle into the hole, but if you've taken it apart and cleaned it off this is very unlikely. It can be due to a very mis-bent metal strip that adjusts the relationship between float height and needle valve position. But before you start messing with that strip, which really should not need adjustment unless it fell on the ground and was stepped on during carb disassembly, I would seriously re-rule out all other reasons for fuel not getting into the carb in the first place.

thanks so much for the help and info