squirty SU's

druid · Sep 26th, 2006, 18:13

My rear carb spills petrol at a scary rate from the little vent by the fuel line

do any of you know the problem? could it be the fuel pump?

i ask that cos the petrol was still pumping out for a few seconds AFTER the engine stopped running, any help guys??

Oh yeh i put my finger over the hole and the motor cut out!

222s · Sep 26th, 2006, 18:58

I had this same problem the other month & it caused a full tank to last just 65 miles.......

The prime suspect is usually a bit of crud in the float chamber jet, which is stopping the float closing the valve that shuts off the fuel flow. It could also be a damaged jet or jet valve seat, but most likely to be crud

You'll need to remove the float chamber lid from the carb, and then very gently knock out the small bar that holds the float chamber to the lid - it will normally only go one way - look to see where the knurled end is. Once that is off, the jet can then be lifted out for inspection, & cleaning of the seat. Reassembly is the reverse of disassembly, except you swear in different places

I'd also recommend replacing all the underbonnet fuel hoses and fitting a fuel filter, in case the problem is being caused by the innards of the old hoses breaking up.

Hope this helps

pookie · Sep 26th, 2006, 20:48

When the float is in your hand, shake it by your ear. If it rattles its punctured and you need a new float. A punctured float gives the same problems as you describe, because it doesn't sit in the fuel at the correct level to shut off the needle valve.

Pookie

amazondean · Sep 26th, 2006, 22:06

You are best fitting the fuel filter before the pump so that the pump does not get crud in it. I have a filter before and after the pump to make sertain.

druid · Sep 27th, 2006, 14:27

the carbs have been rebuilt and i know the float is ok so i will go down the route of crud again but why is it still coming out like its under pressure?

pookie · Sep 27th, 2006, 21:39

The fuel is coming out under fuel pump pressure. The needlle valve is open,so the fuel fills up the float chamber and then out via the overflow pipe.

Pookie

222s · Sep 27th, 2006, 22:19

Quote:

Originally Posted by pookie

The fuel is coming out under fuel pump pressure. The needlle valve is open,so the fuel fills up the float chamber and then out via the overflow pipe.

Pookie

Exactly! From my own experience, I can confirm that the fuel won't be just dribbling out - it's a constant jet

Makes a nice noise when it hits the hot exhaust manifold / downpipe too.....

druid · Sep 28th, 2006, 15:57

ok but why is it still squirting AFTER the engine has stopped? could it be the fuel pump? is there a relief valve in it to stop it pumping when the float chamber is full?

222s · Sep 28th, 2006, 16:44

Quote:

Originally Posted by druid

ok but why is it still squirting AFTER the engine has stopped? could it be the fuel pump?

If it does so just for a moment or so after the engine has stopped, then it's probably just residual pressure in the fuel lines, but that's not why it's squirting out in the first place.

Have you replaced the pump recently? I vaguely recall reading something about some of the new ones being too high a pressure, but I'm sure that one of the experts will be able to provide more info.

Quote:

Originally Posted by druid

is there a relief valve in it to stop it pumping when the float chamber is full?

Yes - that's the float chamber jet!!! Basically, when fuel reaches a certain level, the float is pushed against the jet, & closes it. This prevents additional fuel entering the float chamber before the fuel level in there has dropped. However a piece of crud (innards of fuel line breaking up, muck from the bottom of the fuel tank etc) can easily get stuck in the jet, preventing it from closing properly & therefore allowing fuel to keep entering the float chamber. This excess fuel then exits via the overflow.....

druid · Sep 28th, 2006, 21:30

cheers paul, time to get the fuel filter fitted - its no good by my bread bin is it

Sep 26th, 2006, 18:13	#1
druid V40 Owner Last Online: Dec 13th, 2020 01:28 Join Date: Aug 2006 Location: Tonyrefail, Souh Wales. View Photos By: druid	squirty SU's My rear carb spills petrol at a scary rate from the little vent by the fuel line do any of you know the problem? could it be the fuel pump? i ask that cos the petrol was still pumping out for a few seconds AFTER the engine stopped running, any help guys?? Oh yeh i put my finger over the hole and the motor cut out!

Sep 26th, 2006, 18:58	#2
222s Amazoniste Last Online: Sep 19th, 2016 21:52 Join Date: Nov 2002 Location: Emsworth View Photos By: 222s	I had this same problem the other month & it caused a full tank to last just 65 miles....... The prime suspect is usually a bit of crud in the float chamber jet, which is stopping the float closing the valve that shuts off the fuel flow. It could also be a damaged jet or jet valve seat, but most likely to be crud You'll need to remove the float chamber lid from the carb, and then very gently knock out the small bar that holds the float chamber to the lid - it will normally only go one way - look to see where the knurled end is. Once that is off, the jet can then be lifted out for inspection, & cleaning of the seat. Reassembly is the reverse of disassembly, except you swear in different places I'd also recommend replacing all the underbonnet fuel hoses and fitting a fuel filter, in case the problem is being caused by the innards of the old hoses breaking up. Hope this helps __________________ Paul - 1967 Amazon 222S B20 o/d Estate & 1961 A-H Sprite Mk2 948cc WANTED - For '67 Amazon estate - offside rear quarter, preferably new old stock.

Sep 26th, 2006, 22:06	#4
amazondean amazondean Last Online: Apr 25th, 2024 19:27 Join Date: Oct 2004 Location: Nettleton Market Rasen	You are best fitting the fuel filter before the pump so that the pump does not get crud in it. I have a filter before and after the pump to make sertain. __________________ There are only two things in life that is easy. One's lying down and the other is handing your credit card over. everything else has a degree of skill. Volvo 850 TDI, 850 TDI, 850 TDI Volvo V70 TDI, V70 TDI, Volvo V70 XC, (99)

Sep 26th, 2006, 20:48	#3
pookie Premier Member Last Online: Apr 2nd, 2021 21:13 Join Date: May 2006 Location: Stockport	When the float is in your hand, shake it by your ear. If it rattles its punctured and you need a new float. A punctured float gives the same problems as you describe, because it doesn't sit in the fuel at the correct level to shut off the needle valve. Pookie

Sep 27th, 2006, 14:27	#5
druid V40 Owner Last Online: Dec 13th, 2020 01:28 Join Date: Aug 2006 Location: Tonyrefail, Souh Wales. View Photos By: druid	the carbs have been rebuilt and i know the float is ok so i will go down the route of crud again but why is it still coming out like its under pressure?

Sep 27th, 2006, 21:39	#6
pookie Premier Member Last Online: Apr 2nd, 2021 21:13 Join Date: May 2006 Location: Stockport	The fuel is coming out under fuel pump pressure. The needlle valve is open,so the fuel fills up the float chamber and then out via the overflow pipe. Pookie

Sep 28th, 2006, 15:57	#8
druid V40 Owner Last Online: Dec 13th, 2020 01:28 Join Date: Aug 2006 Location: Tonyrefail, Souh Wales. View Photos By: druid	ok but why is it still squirting AFTER the engine has stopped? could it be the fuel pump? is there a relief valve in it to stop it pumping when the float chamber is full?

Sep 28th, 2006, 21:30	#10
druid V40 Owner Last Online: Dec 13th, 2020 01:28 Join Date: Aug 2006 Location: Tonyrefail, Souh Wales. View Photos By: druid	cheers paul, time to get the fuel filter fitted - its no good by my bread bin is it

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