classic car forum header
Classic cars forum & vehicle restoration.
 FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 
How To Register     Posting Photographs     Privacy Policy     F/book facebook.com/oldclassiccar

Leaking petrol
Post new topic   Reply to topic    Classic cars forum & vehicle restoration. Forum Index -> Austin
Author Message
Austin100



Joined: 06 Nov 2018
Posts: 42
Location: Denton

PostPosted: Mon Dec 17, 2018 8:39 am    Post subject: Leaking petrol Reply with quote

Hi all
I have a problem with leaking petrol I think from the inlet manifold gasket.
The symptoms are when the engine is to be started from cold the choke is pulled fully out and after a few turns of the engine petrol can be see running down the engine block below the intake manifold. It is hard to see exactly where from as the exhaust manifold is partly in the way. It is not leaking from the carb where it mounts onto the inlet manifold but I think from the manifold where it bolts to the engine.
Any thoughts please.
Should the carb be pumping so much fuel through I thought the float in the carb would limit it. Car is Austin 10 gs1 1946.
Many thanks
Peter
Back to top
View user's profile Send private message
ukdave2002



Joined: 23 Nov 2007
Posts: 3353
Location: South Cheshire

PostPosted: Mon Dec 17, 2018 10:22 am    Post subject: Reply with quote

When the fuel leaves the carb it should be atomised (not a liquid) . With the engine running there will be a vacuum in the manifold, so you would expect excess air entering the engine, not a fuel leak

I suspect the fuel is leaking from the carb and running down the manifold.

Dave
Back to top
View user's profile Send private message Visit poster's website
Austin100



Joined: 06 Nov 2018
Posts: 42
Location: Denton

PostPosted: Mon Dec 17, 2018 11:07 am    Post subject: Reply with quote

Thanks Dave
Just a point the engine is not running when this happens just being turned via the starter motor. The carb is a zenith 30vm4 and sits quite high on the manifold i could not see any leaks from around the gasket which joins carb to manifold.
I have now taken carb off and looking down the manifold there was petrol at the bottom where it branches to the ports.
Bit hard to explain !!!
Peter
Back to top
View user's profile Send private message
alanb



Joined: 10 Sep 2012
Posts: 323
Location: Berkshire.

PostPosted: Mon Dec 17, 2018 2:00 pm    Post subject: Reply with quote

Sounds like the carb is flooding, check the float is operating the shutoff valve fully and the valve is not worn, the manual should give the right setting for the float level.
_________________
old tourer


Morris 8 two seater
Back to top
View user's profile Send private message
Austin100



Joined: 06 Nov 2018
Posts: 42
Location: Denton

PostPosted: Mon Dec 17, 2018 5:14 pm    Post subject: Reply with quote

Thanks Alan
Will have a look the carb is off at the moment the float looks ok and does not have any fluid inside also no dints.
I have pushed the valve up with my finger whilst blowing through the carb inlet and the valve is certainly working but if the float is not reaching it won't cut off.
I will have a look to see if the books gives a level a don't know how you could set it as it is free floating.
Cheers
Peter
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic    Classic cars forum & vehicle restoration. Forum Index -> Austin All times are GMT + 1 Hour
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
Forum T&C


php BB powered © php BB Grp.