flak monkey
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| posted on 23/1/07 at 07:31 PM |
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Fuel drip on DCOEs
Sure this has been asked before, but my searches have turned up nowt...
One of the bores of my DCOE's drips fuel occasionally (mainly cylinder 1 but not exclusively), not on tick over, but sometimes on acceleration
and fast running. I think it may be fuel from the accelerator pump jets just running back down the carb bores? Am I correct? I have heard that a bit
of fuel sealant around the face of the trumpet can stop the problem, but I want to be sure its normal and not something that needs looking into?
The carbs arent flooding, fuel pressure is about 1.5psi.
Cheers,
David
Sera
http://www.motosera.com
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Stu16v
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| posted on 23/1/07 at 08:50 PM |
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It sounds like the carb IS flooding - but only very slightly. Check float levels, condition of needle valves, floats for sticking, rubbing against
side of body etc
Dont just build it.....make it!
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flak monkey
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| posted on 23/1/07 at 08:52 PM |
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I was under the impression that if the carb flooded the fuel would come out of the fuel bowl vent on the front of the carb, not out of the bore?
And the carbs were completely rebuilt before fitting. So should be ok, but its worth checking...
[Edited on 23/1/07 by flak monkey]
Sera
http://www.motosera.com
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Stu16v
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| posted on 23/1/07 at 09:10 PM |
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Fuel will come out of any hole it is not supposed to come out of if the fuel level is too high. Jets included. It might not leak when the engine isnt
running, but with the slight 'pull' on the jets once running, will tip the fuel 'over the edge' so to speak.
Dont just build it.....make it!
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flak monkey
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| posted on 23/1/07 at 09:13 PM |
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Ok, thanks for that  I will check the float levels etc when i get back to the car.
Other suggestions welcomed...
Sera
http://www.motosera.com
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dave-69isit
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| posted on 23/1/07 at 09:50 PM |
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drip
dave hav you got a pressure regulater on your pump maybe to high feeding to much fuel
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flak monkey
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| posted on 23/1/07 at 09:52 PM |
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Yeah facet pump, regulated down to about 1.5psi at the mo, as is recommended for dcoes.
Sera
http://www.motosera.com
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mark chandler
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| posted on 23/1/07 at 10:11 PM |
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Bolted up to tight ?
If you bolt solidly and do not us the funny sprung washers (cannot remember what they are called) then you overcompress the 'O' rings on
the manifold, fuel froths and dribbles out the back.
Regards Mark
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CairB
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| posted on 23/1/07 at 10:30 PM |
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Thackery washers ?
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flak monkey
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| posted on 24/1/07 at 07:12 AM |
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Attached with thackery washers as per webers recommendations
Sera
http://www.motosera.com
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Dave-M
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| posted on 24/1/07 at 04:57 PM |
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Hope this can help you, It has worked for me before.
1) if the float level was wrong it would leak equally from each choke and run crap at idle,as this is not the case you can assume your settings/fuel
pressure are OK.
2)As it only happens at wider throttle openings I think it's safe to say that the fuel is leaking from around the perimeter of the auxilliary
venturi as this only has fuel passing through it at wider throttle openings. The leaked fuel finds it's way forward to leak from the bottom of
the bellmouth / carb body joint.
3) The fix is one of the following. a) replace the aux venturi with one which is not damaged or has a better fit in the carb body. b) Fit the
bellmouth to the carb body using Wellseal or similar. c) Goto your local hydraulics place and find a suitable O ring to fit in the recess between
bellmouth and carb body. it will need to be a thin cross section O ring but it's the fix that I prefer.
Do all 4 bellmouths while you are at it.
HTH
Regards
Dave
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flak monkey
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| posted on 24/1/07 at 05:03 PM |
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Thank you very much Dave. You have confirmed my initial thoughts. It is only a very slight leak, and barely drips, but is wet if you run your finger
across the bottom of the trumpet.
It runs fine at idle, and is only leaking on the one choke.
As it seems like there is nothing technically 'wrong' with the carbs then I will find a way of sealing the trumpet to the body, probably
with an o-ring as you suggest.
Many thanks
David
Sera
http://www.motosera.com
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Stu16v
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| posted on 24/1/07 at 05:08 PM |
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quote:
Originally posted by Dave-M
Hope this can help you, It has worked for me before.
1) if the float level was wrong it would leak equally from each choke and run crap at idle,as this is not the case you can assume your settings/fuel
pressure are OK.
Assuming that the carbs/engine/car is perfectly level too...
Dont just build it.....make it!
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