OP
UTC

Member
ET4 125cc 2002
Joined: UTC
Posts: 5
Location: Corfu Greece
 
Member
ET4 125cc 2002
Joined: UTC
Posts: 5
Location: Corfu Greece
UTC quote
Hi All,
Just registered as need some help. Vespa ET4 125cc 2002 model and have stripped carbs down and cleaned, main jet, idle jet, holes under diaphram.. it will start for about 20 seconds and then cut out. The vacuum line doesn't appear to open the valve tank valve while connected to the carb. If you remove and suck it does start and maintain running, is this a carb issue with not creating a vacuum or is it the extra negative pressure on the tank valve when sucking the hose.
Appreciate any help.
@slowpoke avatar
UTC

Hooked
1952 allstate (early), 1958 allstate, 2009 S150, 2001 ET2
Joined: UTC
Posts: 226
Location: CT
 
Hooked
@slowpoke avatar
1952 allstate (early), 1958 allstate, 2009 S150, 2001 ET2
Joined: UTC
Posts: 226
Location: CT
UTC quote
Can you post a pic of where you have the lines on your carb hooked up? It most likely is the fuel tap that needs to be replaced.
OP
UTC

Member
ET4 125cc 2002
Joined: UTC
Posts: 5
Location: Corfu Greece
 
Member
ET4 125cc 2002
Joined: UTC
Posts: 5
Location: Corfu Greece
UTC quote
Hi Slowpoke,
Not sure why I'm struggling to post a pic, sorted… fuel line is top of the vacuum tap and goes to rhs of carb at high level, vacuum line come from lower lhs of carb and you have a drain line from carb bowl that drops to bottom of bike.
Forum member supplied image with no explanatory text
Forum member supplied image with no explanatory text
@slowpoke avatar
UTC

Hooked
1952 allstate (early), 1958 allstate, 2009 S150, 2001 ET2
Joined: UTC
Posts: 226
Location: CT
 
Hooked
@slowpoke avatar
1952 allstate (early), 1958 allstate, 2009 S150, 2001 ET2
Joined: UTC
Posts: 226
Location: CT
UTC quote
What's with the fuel filter that is installed on the EVAP line? There is no fuel filter installed on these bikes since there is a screen on the fuel petcock. The fact the fuel filter looks to be on a vacuum line might be causing a drop in pressure.
Also I would cut that zip tie and on twist the lines up at the gas tank.
@slowpoke avatar
UTC

Hooked
1952 allstate (early), 1958 allstate, 2009 S150, 2001 ET2
Joined: UTC
Posts: 226
Location: CT
 
Hooked
@slowpoke avatar
1952 allstate (early), 1958 allstate, 2009 S150, 2001 ET2
Joined: UTC
Posts: 226
Location: CT
UTC quote
LX150 Complete EVAP System Removal
Here is an EVAP removal article, for reference you can use this to make sure yours is hooked up correctly.
OP
UTC

Member
ET4 125cc 2002
Joined: UTC
Posts: 5
Location: Corfu Greece
 
Member
ET4 125cc 2002
Joined: UTC
Posts: 5
Location: Corfu Greece
UTC quote
Hi Slowpoke,
I've checked and I don't believe my ET4 has an evap system, on the petcock what nipple is the vacuum line and what is the fuel line. Top or bottom?
UTC

Molto Verboso
'07 GTS250, '07 LX150, '81 P200E, '78 P200E, '64 V90 and 3 Ciaos
Joined: UTC
Posts: 1182
Location: Tucson, AZ
 
Molto Verboso
'07 GTS250, '07 LX150, '81 P200E, '78 P200E, '64 V90 and 3 Ciaos
Joined: UTC
Posts: 1182
Location: Tucson, AZ
UTC quote
Is it me, or do the fuel and vacuum lines look reversed? Vacuum should be on the bottom of the tap, so it can pull down the tap diaphragm and allow fuel to flow.

Where does the "T" branch of the black/green hose go? I believe that should be on a carburetor vent pipe if you don't have an evaporative emissions system.
OP
UTC

Member
ET4 125cc 2002
Joined: UTC
Posts: 5
Location: Corfu Greece
 
Member
ET4 125cc 2002
Joined: UTC
Posts: 5
Location: Corfu Greece
UTC quote
Vacuum line is connected to the lower nipple on the petcock, but the carb is either not creating a vacuum or the petcock is not pulling down because due to it being faulty.. if you suck the vacuum line the bike will run. Think I will change the petcock and remove the bin line fuel filter.
The T section goes to the inlet manifold after the carb.
Forum member supplied image with no explanatory text
@slowpoke avatar
UTC

Hooked
1952 allstate (early), 1958 allstate, 2009 S150, 2001 ET2
Joined: UTC
Posts: 226
Location: CT
 
Hooked
@slowpoke avatar
1952 allstate (early), 1958 allstate, 2009 S150, 2001 ET2
Joined: UTC
Posts: 226
Location: CT
UTC quote
The in line filter will slow speed of fuel on these gravity feed scooters. The fuel petcock is most likely your problem here.
Let us know if that fixes it.
UTC

Molto Verboso
'07 GTS250, '07 LX150, '81 P200E, '78 P200E, '64 V90 and 3 Ciaos
Joined: UTC
Posts: 1182
Location: Tucson, AZ
 
Molto Verboso
'07 GTS250, '07 LX150, '81 P200E, '78 P200E, '64 V90 and 3 Ciaos
Joined: UTC
Posts: 1182
Location: Tucson, AZ
UTC quote
Where is the gray line from the fuel tap vacuum port connected? It looks like it's on the fuel inlet for the carb.

I suspect the terminating locations of the green and grey sleeved hoses might be reversed. You shouldn't be fuelling your engine through the vacuum port on the intake manifold.
OP
UTC

Member
ET4 125cc 2002
Joined: UTC
Posts: 5
Location: Corfu Greece
 
Member
ET4 125cc 2002
Joined: UTC
Posts: 5
Location: Corfu Greece
UTC quote
The carb has 3 hoses
1. Fuel line comes off T section and connects high on the rhs of carb below diaphragm cover.
2. Vent line connects to the carb below choke connection on lhs
3. Drain line from bowl on bottom
DoubleGood Design banner

Modern Vespa is the premier site for modern Vespa and Piaggio scooters. Vespa GTS300, GTS250, GTV, GT200, LX150, LXS, ET4, ET2, MP3, Fuoco, Elettrica and more.

Buy Me A Coffee
 

Shop on Amazon with Modern Vespa

Modern Vespa is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to amazon.com


All Content Copyright 2005-2024 by Modern Vespa.
All Rights Reserved.


[ Time: 0.0156s ][ Queries: 5 (0.0078s) ][ live ][ 313 ][ ThingOne ]