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Weber DCOE40 questions

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Wait, it was once on a Fiat?? I don't know if I can touch it now.
 
No, its 31. So that refers to the choke size? I need to buy the book on these.
 
On two of mine it does. They are from an Alfa which is what I meant to say earlier. That commercial got me screwwed up. It's a long shor but your might be rare.
 
Nice find. Now to read up on what it is I have.
 
Hi
I just bought a new DCOE 40 has 30mm choke F11 115 Main jet 45 F9 Idle jet. Will this work on a 948 with an aluminum head and headers.
I am installing today.
 
You can save time and frustration by having it put on a dyno and tuned by professionals. There are way too many stories of guys buying a bunch of jets (not cheap) changing, tuning, fiddling, resetting, adjusting, etc and never being able to get rid of the "off idle stumble" while at the same time having a decent idle. I have a DGV that I had done by the pros and runs just right. The idle is the same (once its warmed up) in 40 degree weather or 90 degree weather or when the engine (water) temp is 165 or 200. (More than I could ever say about SUs). It doesn't stumble hic-up or hesitate.. well to be honest if I'm doing 65 mph and FLOOR it there is millisecond delay before it ROARS away down the road. There has to be shop nearby that can get it set up for ya.... unless that is you just love to tinker (incessantly)
 
iMO DCOE are are hobby in themselves,unless you have experience with them or have a club member who does
you are going to end up with a tackle box full of parts before you ever get it rite.
The joke back in the day was if you take a webber apart enough times at some point you end up with two.
I would stick with a nice set of simple reliable easy to tune HS 2's
 
SD Bugeye said:
iMO DCOE are are hobby in themselves,unless you have experience with them or have a club member who does
you are going to end up with a tackle box full of parts before you ever get it rite.
The joke back in the day was if you take a webber apart enough times at some point you end up with two.
I would stick with a nice set of simple reliable easy to tune HS 2's
Click to expand...
I already have 2 a 45 and a 40. The idle jets in the 45 are are 55 F8 with a 32 mm choke, the main jet are F16 with a 140 tip. At first this set up worked ok. Just had a stumble coming off Idle. But after a while the spark plugs became very black. every one said the 45 are too big. so new plan buy 40 and sell the 45. After installing the 40 and checking it for sync and good idle. I took it for a run. Very poor acceleration off of idle almost dies when cold. After warm up it still did not come off of idle without a big stumble. The idle jets are 45 F9 with a 30 mm choke. I took the idle jets out of the 45 and installed them in the 40 big improvement. No stumble off of idle. However I think it is running a little lean in the middle to top end. I think a smaller choke or a larger Main jet will get me close. Monday a color tune spark plug will arrive. I think this will help give me a direction on which way to go. I bought this from carbs unlimited and their tech guy can help if I give him what I see in the color tune. I live out in the dingy weeds no help for miles around.
 
did another test drive this morning. choke it not yet connected, had one stumble trying to get going. After that none from a stop or from a shift. however it does stumble at and above midrange. I think it may be too lean in this area. I removed a plug and it was a light tan color. Now I have to figure out what to change, smaller choke, larger main jet or smaller air correction jet. any suggestions would be helpful. Sorry not going back to SU
thanks
Sim
 
Sim
A few questions. Do you have a fuel pressure regulator? I understand these carbs like a lower pressure than stock. What are you doing with your vacuum advance? You might have to get you D25 distributor curved. Lastly how are you venting your valve cover ( not a carb problem, but I understand you need vacuum to prevent oil leaks)
Regards
Paul
 
apbos said:
Sim
A few questions. Do you have a fuel pressure regulator? I understand these carbs like a lower pressure than stock. What are you doing with your vacuum advance? You might have to get you D25 distributor curved. Lastly how are you venting your valve cover ( not a carb problem, but I understand you need vacuum to prevent oil leaks)
Regards
Paul
Click to expand...
Hi yes do have a regulator about 2.5 lbs Vacuum advance is taken for the intake manifold. Have not checked to see if it is working. I did check and adjusted timing added a bit more. Not sure where it is. I need to make some new timing marks. As I installed a different damper and the chain cover was a bit different. I am running pentronic ignition in a new distributor. Cables are less than a year old and I have new plugs.
 
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