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carbs leak fuel into engine overnight!
type3lover - March 18th, 2005 at 05:27 PM

Hey all,
I got into the kombi to go to work this morning and it wouldn't crank over at all. Opened the engine lid and noticed that the carb on the right had petrol all over the outside and had run down the manifold and even leaked onto the ground.
Then I managed to get it to crank over and saw heaps of fuel vapours coming out the exhaust. Had to remove the plugs on cylinders 1 & 2 and then crank the starter to expel all the fuel that had filled the engine overnight. Also took off the carb and checked needle and seat for any any sign of sticking, tightened everything and put it all back together. Runs fine - no leaks. Basically the cylinder full of fuel was "hydraulicing" - since liquid cannot be compressed as the piston tries to travel up the bore and that's why it wasn't cranking over at all.
BUT...this is the second time this has happened now. Last time was the left carb.
What is going on? Anyone ever had this happen?

Car: 1976 kombi
Engine: 2 litre
Carbs: standard solex 34PDSIT
Fuel pump: electric

TIA for any advice!
Toby

[Edited on 18-3-2005 by type3lover]


toplessbug - March 18th, 2005 at 08:07 PM

your bum is lower than your front, fuel siphons from the carb bowl up the vent tube and down the venturi thru the open valve and presto a guts full of fuel.. the easiest fix is reverse into your parking spot so your bum is in the air


kombibob - March 18th, 2005 at 08:20 PM

faulty needle and seat 'remove and replace
and dont drive without a oil change


68AutoBug - March 18th, 2005 at 10:02 PM

Yes, VERY Important to change Your oil as fuel will have leaked past the rings into the sump....

Take out the dipstick & smell it.... it will smell like petrol....

The oil is diluted with petrol.... Don't drive the vehicle....

Needle & seats should be changed in both carburetors...
the fuel is running into the fuel bowl in the carburetor
[thru the needle & seat] & overflowing into the inlet manifold.

I always renew the needle & seat every few years....
they do wear out and leak.... thats why they are renewable.

Lee

http://community.webshots.com/user/vw68autobug 


Midlife crisis - March 18th, 2005 at 10:45 PM

I also put a fuel cutoff switch from a LPG system in the fuel line where it comes out the tunnel with the wire going to the coil to power the switch just a backup.

Marc

[Edited on 18-3-05 by Midlife crisis]


68AutoBug - March 18th, 2005 at 10:48 PM

Although a fuel cutoff switch is a great idea, I have one...
it won't stop the needle & seat from leaking....
it can happen in traffic if the carburetor is full and the needle & seat start leaking.... the engine will flood and cut out....

Its best to replace the needle & seat...

Lee


BUS-234 - March 18th, 2005 at 11:02 PM

Yeah this same thing has happened to me two or three times before. i used to have a lot of crap in the fuel tank and a particle must have got stuck in the jet and left it open, i park on an incline too. so basically the same thing happened. now im running three fuel filters, one at the outlet of the tank and one just before each carbie. havent had the problem since. as the guys said u will need to change your oil too


type3lover - March 19th, 2005 at 03:06 PM

Shit I drove it to work (about 3km). Am I doomed for engine leaks/failure?
Oil level is normal, and I only changed it last week. Used ACE 30 too!
I usually park on an incline in my driveway so that might be making the problem worse. Tonight I reversed in instead!
Last time it filled the sump with fuel but this time seems quite minor.
I can't understand why so much fuel has made its way past the pump!
Any details on the LPG valve?
Also do I need a full carby kit or is the needle and seat available as a separate part?
Thanks so much!
Toby


Anthiron - March 19th, 2005 at 03:54 PM

u can buy needle and seats seperate to the carby kit. but if u are going to do it u may as well do the whole carbys. ive had this problem and rebuilt my carbie and now it seems ok tho i still try not to park nose up. change your oil anyway.


type3lover - March 25th, 2005 at 04:12 PM

Parking the van bum up in the driveway seems to have stopped any problems. New carb kits have been added to the wish list :-) which is getting longer and longer...
Pity to have to do the carbs since it drives so well usually.
Cheers!
Toby


68AutoBug - March 25th, 2005 at 04:20 PM


Hi Toby,
Just buy the needle & seat kits....

take the top off the carby & replace them....

but price both first as a full kit may be the same as a needle & seat....

Late Beetles had a cutoff valve in the fuel pump.....

or just keep parking back to front... :):)

Lee


h - March 25th, 2005 at 10:47 PM

definatly faulty needle and seat had this prob many times with several bays..
'remove and replace and dont drive without a oil change as fuel in oil not good to drive on.. check fo fuel in oil (smell) ;)
all very impotant tips and just before you install your needle n seats check that they dont and wont get stuck open manually wif fingers cause if they do try n get some more that wont..
painful but ya gotta do it for ya bus man.. :)

[Edited on 25-3-2005 by h]