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davidbradley
New user
Joined: 27 Jan 2008
Posts: 3
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 Posted: Tue Feb 05, 2008 8:34 pm Post subject: DCOE problems |
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Hi
I have a car that generally wont start, it's fitted with twin 40s
After a short bit of trying to start, there is fuel dripping from the throttle mouthson all four inlets.
I've changed the needle valves, cleaned the pump jet ball valves, and fitted a regulator (set a 2psi)
Nothing has changed/improved.
Float levels are set at 8.5mm, 15mm
If I remove the trumpets & take out the Aux venturis the car will often start, though there is still fuel everywhere.
Finally, after a few turns of the starter, fuel collects in the chamber that allows the air pressure at the top of the carb to match the air intake.
So I wonder if the level is too high - though set at 8.5mm
The floats are brass, and dont seem to have fluid in them if shaken
I'm stuck, and would appreciate any ideas anyone may have.
Thanks |
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Steve Williams
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Joined: 09 Dec 2007
Posts: 8
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| Posted: Tue Feb 05, 2008 11:38 pm Post subject: |
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2 possibilities if the floats are set correctly:
1. Dirt in the needle valves, causing them not to close properly. Make sure you have cleaned them out thoroughly.
2. Worn needle valves allowing fuel to flow into float chamber even when float chamber is full. Replace needle valves with new. The genuine Weber service kit contains these, usually the 1.75 size valves. |
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davidbradley
New user
Joined: 27 Jan 2008
Posts: 3
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| Posted: Wed Feb 06, 2008 7:11 pm Post subject: |
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Many thanks
The needle valves have been replaced, with 175s
I think I have the floats set correctly, but I agree that there's something wrong there somewhere.
Whereas both carbs do it a bit, one is much worse than the other - the floats are set the same, which makes me think it's not my floating setting abilities (limited though they are) but excess fuel pressure (though set at 2psi, and both carbs getting the same) or duff floats - worst on the left.
The new valves havent helped (in fact things feel slightly worse) and it's still the left carb that is the worst, just as it always was.
Could anyone describe what the fuel level should be with the carb top removed, so I can see if there is indeed too much petrol in there?
I'll also try switching the tops over, and see if the worst of the problem changes from left to right.
All suggestions gratefully received |
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bigjim5551212
Enthusiast
Joined: 11 May 2007
Posts: 53
Location: Vancouver Canada
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