OP
UTC

Member
LX50 2T
Joined: UTC
Posts: 7
Location: Belgium
 
Member
LX50 2T
Joined: UTC
Posts: 7
Location: Belgium
UTC quote
Hello everyone!
I bought a Vespa LX50 2T that needed some attention.
I did a complete teardown, gave it a paint job an reassembled everything, in the meanwhile I did the following engine jobs:

-replaced air filter
-replaced spark plug
-Replaced fuel/vacuum lines and fuel filter
-Replaced drive belt for the oil pump and lines
-Cleaned carburator
-brakes, belts, vario rolls, ......

The engine starts with one kick, runs great on idle but when I drive the Vespa it stalls when give it a full throttle. It doesn't do that the first 30sec... when lossen the gas it runs fine again...
I did the following checks:

-Re-cleaned the carb en checked everything
-Put wd40 on the inlet manifold, cilinder, lines... no change in idle..
-checked the vacuum line
-I see fuel running in the fuel line
-unplugged the choke
-played with the air/fuel mixture
-...

Nothing helps, I'm a bit stuck for the moment and don't know what to do next, any help would be appreciated!
THX!
@kz1000st avatar
UTC

Molto Verboso
Dongfang 170cc, CF Moto Fashion 250
Joined: UTC
Posts: 1889
Location: Hyde Park, New York
 
Molto Verboso
@kz1000st avatar
Dongfang 170cc, CF Moto Fashion 250
Joined: UTC
Posts: 1889
Location: Hyde Park, New York
UTC quote
Either crud in the tank restricting fuel flow at at max requirements or the tank vent is also restricted at the cap or vent hose. The carb is running dry at full throttle.
UTC

Veni, Vidi, Posti
Joined: UTC
Posts: 7058
Location: Tega Cay, SC
 
Veni, Vidi, Posti
Joined: UTC
Posts: 7058
Location: Tega Cay, SC
UTC quote
If it runs great the first 30 seconds, it is running with the choke circuit involved = richer than when warm. I think you should check the carb again, specifically the slide diaphragm for holes and the main jet.
OP
UTC

Member
LX50 2T
Joined: UTC
Posts: 7
Location: Belgium
 
Member
LX50 2T
Joined: UTC
Posts: 7
Location: Belgium
UTC quote
Thanks for the tips!!!

I tried to run the engine wothout the fuel cap, no changes. The fuel line is full of fuel so I think thats ok.
I noticed that when I play with the trottle there is some fuel comming in the vacuum line on the carb side, don't know is this normal?

The platic cap on the choke gets realy hot when the engine runs for couple of min. Is that something to worry about?
When I disconnect the choke the results are the same…

Spent hours on this issue and it realy begins to frustrate me😡
@pinkscooter avatar
UTC

Addicted
GTS 250ie Super, Italjet Velocifero, Scarabeo 150, S50, ET4, ET2
Joined: UTC
Posts: 713
Location: Winston-Salem, NC
 
Addicted
@pinkscooter avatar
GTS 250ie Super, Italjet Velocifero, Scarabeo 150, S50, ET4, ET2
Joined: UTC
Posts: 713
Location: Winston-Salem, NC
UTC quote
Tierney wrote:
If it runs great the first 30 seconds, it is running with the choke circuit involved = richer than when warm. I think you should check the carb again, specifically the slide diaphragm for holes and the main jet.
This is a 2T and doesn't have the CVK carb so no diaphragm.

The enricher running hot is normal. You shouldn't get fuel on the vacuum line. The petcock could be going and the diapraghm could be leaking. That fuel would be causing the scooter to be getting too much gas.
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