timwest167
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| posted on 13/2/06 at 11:11 AM |
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Help - Massive Fuel Leak!
Help!
Tried running my engine for the second time and I had petrol absolutely pouring out of the first carb + dribbling out of the second!
I have a facet fuel pump (6-7psi) connected to a FilterKing regulator (3psi factory setting) connected to twin webbers. I've disconnected the
carbs from the regulator, fixed a length of hose to the regulator and clamped the end to simulate a full float chamber - the pressure gauge measures
3psi. This isn't too high is it?
I've opened both carbs and the floats are free to move. I suppose the floats may be fouling on the inside of the chamber - but how can you tell
when they come off with the cover plate?
Is my facet pump to high a pressure?
Can anybody help please - I'm scared to try it again
Tim
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mookaloid
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| posted on 13/2/06 at 11:22 AM |
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It could be the needle valves not seating or sticking.
if you have had the carbs apart it is possible that they were not assembled correctly. just ease the tops up a bit and check that the floats are
moving correctly.
HTH
Mark
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gary gsx
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| posted on 13/2/06 at 11:23 AM |
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Are the floats closing the needle vavle????
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DarrenW
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| posted on 13/2/06 at 11:30 AM |
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I started with Facet red top feeding my 38DGAS thro a regulator on Pinto.
First problem was knackered accelerator pump diaghpragm. Fuel leak was generous. Fixed that then found out that floats were being overcome with too
much fuel even with reg on lowest setting. Pulsing of the pump meant fuel was being forced thro regulator. Had fires in the carb choke!!! Fix was
going back to mechanical pump - no more issues since.
If you insist on electric pump you may need low pressure solid state facet.
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timwest167
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| posted on 13/2/06 at 11:34 AM |
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Thanks for the replies...
The carbs are new and leaked before I removed the top cover.
When I had the top cover removed I blew in the fuel inlet and then moved the floats - this had the expected result of stopping my blowing - like
you'd expect if the chamber was full of fuel.
Tim
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Nick Skidmore
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| posted on 13/2/06 at 01:02 PM |
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Webber fuel pressure should be 2psi max.
Sometimes the fuel will leak if the carbs have stood a while, this suddenly stops with no explanation!
Try lower fuel pressure first.
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NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
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JoelP
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| posted on 13/2/06 at 01:43 PM |
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use a bike pump. Its so simple it almost makes me sick  There are many reasons to use one, and i cant think of any against it. Does anyone have a
reason not to use bike pumps?!
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02GF74
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| posted on 13/2/06 at 02:09 PM |
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put petrol into a small container connected by a tube and hold above levle of carbs.
you have fuel under gravity - if the carbs still leak; then you have needle valve/flot or other car problem.
if not, then ful pump or regular are at too high pressure - but regulator should solve that.
Have you tried to adjist it? (there is a screw under the domed not; not sure but I think undoing it lessend the pressure)
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mark chandler
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| posted on 13/2/06 at 02:11 PM |
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Are the carbs done up to tight ?
You should have a spring washer behind each nut, you do not fully tighten DCOE carbs, merely nip them up onto to the rubber 'O' ring.
Overtightened = frothing fuel and leaks.
Regards Mark
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britishtrident
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| posted on 13/2/06 at 02:45 PM |
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This problem comes up time and time again --- fit a proper low pressure fuel pump designed for carbs and ditch the regulator.
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timwest167
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| posted on 13/2/06 at 03:17 PM |
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Thanks for the tips, I'll try again at the weekend.
I researched how to supply webbers and was recommended this method. Some people have used the higher pressure competition facets + regulator with no
problem?
Its a little anoying to get this far into the build and have problems with a system others quite happily use 
Thanks,
Tim
PS Britishtrident - Facet do a 2.5 to 3.0 psi pump - can I assume that this would be more suitable (it's also a direct replacement)? Engine is
a zetec, so no mechanical pump.
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britishtrident
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| posted on 13/2/06 at 04:33 PM |
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Regulators can only really work properly in a continuous flow situation -- ie where there is a return line to the tank.
With new carbs it is an idea to check the float valves before fitting the carbs --- turn the carbs upside down and blow into the fuel inlet.
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gazza285
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| posted on 13/2/06 at 05:47 PM |
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Your fuel pump is ok to use with carbs, just turn the pressure down on the regulator.
"Regulators can only really work properly in a continuous flow situation -- ie where there is a return line to the tank."
Not convinced by this as the Facet is an interupter type pump and does not need a return. This combination is tried and tested over many years and
will gives years of reliable service. How does the regulator on my gas bottles work then, if you need a return, or the one on my compressor as these
are both diaphragm type regulators and work in exactly the same way as a Filter King one.
DO NOT PUT ON KNOB OR BOLLOCKS!
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britishtrident
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| posted on 13/2/06 at 07:21 PM |
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I've seen a couple of paddock and also on track fires due to using high pressure pumps on carbs.
Carlos Fandango syndrome.
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gazza285
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| posted on 13/2/06 at 07:26 PM |
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The pump he has is a low pressure pump though, unless you know of an injection system that runs at 7psi?
DO NOT PUT ON KNOB OR BOLLOCKS!
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