weber 40 dcoe 107a request - Alfa Romeo Bulletin Board & Forums

 
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post #1 of 12 (permalink) Old 11-30-2013, 02:05 AM Thread Starter
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weber 40 dcoe 107a request

Has anyone have the exployed view of these carbs? Im having a problem...they leak fuel by the aceleration pumps inyectors. I tried lower the fuel level and nothing happen. They are in sync perfect. The needle valves are new. I think there is something wrong in this circuit. It have a little spring and a bronze cilinder in the bottom of the carb...i think that someone built it and make a mistake with this valve....the position of the spring of something....Thanks from Argentina.....sorry my english.
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post #2 of 12 (permalink) Old 11-30-2013, 06:18 AM
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The 40DCOE106/107 was fitted to some late model 1600's. It was different from other DCOE's that were fitted to Alfa's because it had no accelerator pump back bleed orifice. This information is from Appendix 1 of the Haynes Weber manual.

Ed Prytherch
79 Spider
85 GTV6 3L
76 Suzuki GT500

A little government and a little luck are necessary in life, but only a fool trusts either of them. - P.J. O'Rourke
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post #3 of 12 (permalink) Old 11-30-2013, 06:46 AM
Richard Jemison
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leak

The exploaded view will be the same, only the accel pump bypass jet part number is different.

However if the pump jets are leaking during idle/running then you should check to be sure the check valves are working and the small ball bearing and weight are in place and functioning. Corrosion at the ball seat might be an issue. You might try taking a thin drift/punch and tapping on the ball ro reseat it in the aluminum base.
As well pull the pump jet to insure that the small aluminum washer is in fact on all of the pump jets.

If they are leaking all of the time then your fuel level might be high as you mentioned. That will have a detrimental effect on all of the jetting. Fuel level should be only to the seating base of the main jets. Don`t get hung up on the "float distance" from the top cover as described in most tuning manuals.

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post #4 of 12 (permalink) Old 11-30-2013, 07:40 AM Thread Starter
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Thanks for replies, this modern dcoe don´t have the check balls and the weights like the mosts common dcoe.(is diferent the body of the carb), It only have in the botton of the carb a piece of bronce like a cilinder with a very small spring, besides it have one cero bypass jet like idf´s
I request the exployed view to see the order of that parts, the cilinder of bronce and the little spring, i think that is the problem, maybe it is wrong assembled, i think those pieces works like the check ball and the weight on oldest dcoe.
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post #5 of 12 (permalink) Old 12-09-2013, 02:49 AM
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Memito,

have the same issue with these carbs. They leak a little bit after engine stop.
Have no solution up to now.
I will check the bronce plungers to make sure that they move (and work) easily.
If new results I will post.

Regards
Ralf
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post #6 of 12 (permalink) Old 12-12-2013, 07:51 AM
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I have cleaned everything, plungers move smoothly but still leaking.
Does anyone had this issue and could fix it?

Ralf
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post #7 of 12 (permalink) Old 12-12-2013, 12:26 PM Thread Starter
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ralf my problem is not the same, my carbs dont leak when you turn off the engine, they leak only when the engine is runing, i try to turn off the fuel pump and nothing happend, they leak always, but when i turn of the engine they don`t.
My carburator don`t have plungers and bals like common dcoe. they have another sistem, they have 1¨bronze cilinder¨ and little spring in the bottom of the carb(1 per carb) near to the bottom bowl cover
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post #8 of 12 (permalink) Old 12-12-2013, 01:53 PM
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Here is a link to the Weber Tuning Manual http://www.lainefamily.com/images/WeberTuningManual.pdf

Page 43 talks about accelerator pumps and the fact that there are two types. Maybe the diagrams on this page will help.

Ed Prytherch
79 Spider
85 GTV6 3L
76 Suzuki GT500

A little government and a little luck are necessary in life, but only a fool trusts either of them. - P.J. O'Rourke
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post #9 of 12 (permalink) Old 01-05-2014, 02:19 PM Thread Starter
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thanks for the replies, i fully rebuilt them, i check everything and they still leaking, i dont know what to do, i have 2 pair more but others models and they runs perfect
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post #10 of 12 (permalink) Old 01-06-2014, 03:29 AM
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Meminto,

with plunger I mean this little solid cylinder you have mentioned.
The spring must be fitted on top of this cylinder to push it down.
Hope that helps.

Regards
Ralf
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post #11 of 12 (permalink) Old 01-06-2014, 03:35 AM Thread Starter
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The starter circuit is fully disabled. There was the first test that i made i blocked the exit holes next to the throttle plates
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post #12 of 12 (permalink) Old 03-16-2017, 12:06 PM
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40DCOE 106/107 diagram

Hi,
i know its a long time ago but i have an exploded view of the 40DCOE 106/107,attached if you want it
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File Type: pdf 40DCOE106-107.pdf (1.58 MB, 15 views)
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