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Weber jets??All who live for their triples please read this


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Hey guys.


I’m getting ready to install my new 45 DCOEs and two of the three carburetors have “sticky” throttles. I uploaded a YouTube clip for demonstration purposes.


My Weber book is in storage and I didn’t see any relevant hits in the search results. I’m hoping it’s just the bolts on the side of the butterfly valve, perhaps they are too tight or need some lubricant.


Anyone have any experience or tips here? I’d prefer to not start tinkering randomly…





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I had the issue when doing some tuning for a friend. It happened the brackets holding the pushrods where too close to the carbs, they were rubbing against carb body. We had to add some washers between the carb and the brackets to get some extra clearance. It could also be because the nut of butterfly shaft is too tight.

Try to remove the bracket/hardware to control carbs and check if they are still sticky. Your carbs are most likely fine.

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  • 10 months later...

We're back online!


Many thanks to the admins for restoring "Reply to Post" functionality.


EDIT -- I mistakenly thought I was posting the below post to my engine thread. Oh well! It seems appropriate for this thread too.  :)


I have been kicking the "chassis dyno R&D" can down the road long enough. I have an appointment for Friday, May 4, 2018.


Unfortunately, an air box will not be an option. However, I plan on doing intake volumetric efficiency research with regard to venturi diameters (38mm and 40mm) and the effects of various velocity stacks ("air horns" / "trumpets").


Here are my top air horn picks I am considering:


In my mind, a given length is best, and a given shape is best. These are not necessarily mutually exclusive. I predict the adjustable length will show a "good performance range," and choosing various shapes within this range would reveal optimal combination(s) for a given application. Again in my case I seek a wide, flat torque curve and not peak HP.


Perhaps the data will be clear, but I predict a butt dyno / road test will likely have to confirm / deny the winner(s), especially if some combinations are comparable. WOT hp numbers are not what wins an autocross race.


If anyone is interested in contributing their 45mm air horn shape to this shared research, please message me. I would be happy to return them to you after chassis dyno testing is complete.


Alternatively, air horns, race fuel and dyno time are effing expensive. If anyone is feeling charitable and wishes to donate some coin, that would be appreciated. This project is financed by credit and cash loans; I'm "all-in" with this S30 project. Maybe some others relate?


Some say gains won't be made here. Perhaps in peak hp this is true, but in terms of area under the curve, I defer to Ferrari and other performance companies who have engineered variable length intakes. If it was a gimmick, it wouldn't be on a supercar.


We don't have this data publicly available for our L6s. Let's change that.

Edited by zredbaron
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  • 4 months later...

Maby some of you weber gurus can point me in the right derection her. 


I got a stock l2,6 with full z story exhaust. 

And i have 45mm webers on it. (Got Then with the car (new in box) )


What is a good starting point her? Any rule of tumb on This? My tuner recomeneded me now to order f11 tubes 55f6 idle and 30mm (36mm in Then now) chokes for them. Got alot of option on mains for it from 130-175 i think i was. Air is 170 if i dont remember wrong. 


Hope some one can point me to a start her. Having trubble making it run. Bogs AS soon AS we are trying to rev it if we are not carfull. 


Thank you. 

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  • 6 months later...

Hey to all the experts out there.

I'm a total carb noob and I hope to get a starting point from you.


I'm currently building the engine:


P90 Head (slightly ported)

Something like this "Stage 2" Cam

  • Lift(In/Ex): .480/.480
  • Duration(In/Ex): 274/274

123 Ignition distributor


I currently have a set of DCOE40-151 on my L24 and want to keep using them but  the question is, with which choke and jets should I start?

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It rather depends what you'll do with it. I'd recommend getting this book or one of the others like it.

How to Build and Power Tune Weber and Dellorto DCOE and DHLA Carburettors (Speedpro Series) https://www.amazon.co.uk/dp/1903706750/ref=cm_sw_r_cp_apa_i_Ah7PCb8WCD7AH

They'll help you pick the parts you want for your use case. 


First thing I'd do with them is swap them for 45s.

Edited by jonbill
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  • 4 years later...

Hey guys, noob here. I just picked up a '74 260Z and I need some guidance.

This is what I'm working with;


L26 with E88 heads. Not sure of the internals of the engine but apparently it's been rebuilt (possibly upgraded, possibly stock - who knows).

Canon intake and headers.

Triple 40 DCOE 18

Main - 150

Air - 185

Emulsion tubes - F11

Idle - 50F9

Pump - 45

Aux Venturi - 45

Chokes - 35


Close enough to sea level for altitude.

I balanced the triples and set the idle mixture and speed (to the best of my ability being new to carbs).  Fuel pressure guage says it's getting good 4-5psi.

It's got an AFR meter under the dash and what I'm seeing is that idle is ok and part throttle.  Above about 3,500-4,000rpm with 3/4 throttle to WOT looks ok as well, perhaps a little lean.

The trouble I am having is that anything below 3,500rpm if I step on the gas it bogs down a lot to the point it doesn't go anywhere. So I guess that's the transition from the idle to main circuit.


I would really appreciate some guidance as to what I might try.


engine bay.jpg

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4 hours ago, jonbill said:

Will it get up to the higher revs ok if you don't give it so much throttle?

If it can accelerate up at part throttle without any hiccups, then its probably the accelerator pump circuit.

Yes if I don't stomp on it and give it part throttle to 3,500-4,000 I can stomp on it there and it screams.  Still a bit lean though.

I don't know if the emulsion tubes are correct, or perhaps it could do with a slightly smaller choke?


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On 11/17/2023 at 3:59 AM, jonbill said:

I'd check that the accelerator pump is working correctly first. Take the carbs off and see if they squirt fuel out the back.

Thanks. I did as you suggested and the pumps are all working. I pulled the accelerator jets and cleaned them with some B12, making sure it sprayed out the holes well. Put them back and it improved probably 90%. 

There is still a slight bog/hestitation but it's a hell of a lot better.

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