PHBH carb leak

Anything related to Lambrettas... ask tech questions, post helpful info, or just read and learn.
Blenks
registered user
Posts: 166
Joined: Thu Feb 26, 2015 1:29 pm
Main scooter: Lambretta S3 Li150
Location: Coventry
Contact:

Got to the exciting point today of starting the scooter after a complete strip and rebuild. Started no problem and I think all the electrics are working as they should. I let it run for 5 mins or so but noticed there is a fuel leak on the carb. It is a Dellorto PHBH 30. Seems to be leaking between the float bowl and main body. I don’t believe it was leaking prior to strip but can’t be 100%. So the questions are, is it likely to be the seal? is it an easy task to change the seal on the float bowl? Any setting after doing this. I literally disconnected the hose connecting to the manifold and removed the cables. It has stood for a while though.
User avatar
garry inglis
registered user
Posts: 1298
Joined: Tue Jul 21, 2015 8:04 pm
Main scooter: ts1 230 and rb200
Location: darlington
Contact:

Blenks wrote:Got to the exciting point today of starting the scooter after a complete strip and rebuild. Started no problem and I think all the electrics are working as they should. I let it run for 5 mins or so but noticed there is a fuel leak on the carb. It is a Dellorto PHBH 30. Seems to be leaking between the float bowl and main body. I don’t believe it was leaking prior to strip but can’t be 100%. So the questions are, is it likely to be the seal? is it an easy task to change the seal on the float bowl? Any setting after doing this. I literally disconnected the hose connecting to the manifold and removed the cables. It has stood for a while though.
Just tighten it a bit and they are easy to replace carb gasket kit about £6

Sent from my SM-A320FL using Tapatalk

Adam_Winstone
registered user
Posts: 1693
Joined: Tue Jan 31, 2012 8:54 pm
Main scooter: Lambretta GP
Contact:

Have you fitted a clear float bowl.... they always seem to leak!
Blenks
registered user
Posts: 166
Joined: Thu Feb 26, 2015 1:29 pm
Main scooter: Lambretta S3 Li150
Location: Coventry
Contact:

No I’ve changed anything on the carb at all. It has the standard black plastic float bowl. I’ll order a gasket kit and have a bash at changing them.
User avatar
HxPaul
registered user
Posts: 1110
Joined: Fri Dec 06, 2013 1:58 pm
Main scooter: lambretta Li 150
Location: Halifax,Yorkshire
Contact:

Is the jet holder tightened enough,this doubles as the bolt that fastens the float bowl on.
Mrnice71
registered user
Posts: 111
Joined: Tue Jul 11, 2017 9:41 pm
Main scooter: Lambretta series 3
Contact:

Float height not right , constantly filling bowl , float needs adjusting so it shuts the float needle valve jet off sooner
Blenks
registered user
Posts: 166
Joined: Thu Feb 26, 2015 1:29 pm
Main scooter: Lambretta S3 Li150
Location: Coventry
Contact:

Replaced the float bowl seal and O ring on the bolt and no more leak. Thanks all for the helpful suggestions
Blenks
registered user
Posts: 166
Joined: Thu Feb 26, 2015 1:29 pm
Main scooter: Lambretta S3 Li150
Location: Coventry
Contact:

I was wrong. The leak is still there but not as bad. I have tightened the jet holder bolt as much as I dare. I have never done anything with carbs before so not familiar with issues or assembly. When I removed the bowl I could not see the needle so not sure of the condition. Is there anyway of testing or diagnosing the problem. I’m not too confident of replacing floats etc. I really do not want to start stripping the scooter down again either. Don’t want to run it until this is sorted.
User avatar
HxPaul
registered user
Posts: 1110
Joined: Fri Dec 06, 2013 1:58 pm
Main scooter: lambretta Li 150
Location: Halifax,Yorkshire
Contact:

Is the choke jet seated properly
Blenks
registered user
Posts: 166
Joined: Thu Feb 26, 2015 1:29 pm
Main scooter: Lambretta S3 Li150
Location: Coventry
Contact:

Sorry Paul I have no idea what that is. I wouldn’t know where to start looking for it. Perhaps I should let someone with some knowledge have a look at it for me.
Post Reply Previous topicNext topic
  • Information
  • Who is online

    Users browsing this forum: No registered users and 69 guests