DCOE rich idle - help please!

[Son of Marty]

The stock pump was fine for the ti's and he's running the 6cyl pump as you said webers need volume not pressure to make them happy.

[Chris_B]

52 minutes ago, Stevenola said:

3 isn't too high, but Webers need volume, and I'm not sure a stock mechanical pump can dole out enough gas like a proper electric one can.

I can assure you that it does. I have dual 45DCOEs with 38 chokes and have never had a fuel starvation problem. 

[Son of Marty]

1 hour ago, Son of Marty said:

 

Do your carbs have the cold start levers, If so move the levers a few times then make sure they are seated fully just to be sure they are out of play and not leaking while they are shut.

[Hans]

Maybe the twin Solex carbs have a different design, but when I swapped them for Italian 40s on my NK CS, I had to add a regulator with the stock pump to get it run right. I've played around with fuel pressure, but seems to me between 2.5 and 3 psi gives volume without  overpowering floats. But YMMV. Experiment. 

[ibewebbman]

Ok guys, I spent some time going through the carbs today. I need to spend some more time investigating but thanks to you all I am making progress!

 

so far:

 

1. After inspecting the progression holes I found that indeed I had something hanging up - thanks @TobyB ! I disconnected all the linkage and removed the idle speed screws completely. I now have one of the 3 holes in each barrel covered with everything just sitting there disconnected. Is this right?

 
2. Started the engine with mixture screws out 1.5 turns out won’t idle really anymore and it is clearly not running the same as before with the linkage disconnected and I am getting the fuel weeping issue at the carb filter still ...so

3. Fuel pressure measurement time! fuel pressure seems to be about 4 psi, I measured this by putting a craftsman vac/pressure gauge off a T from the fuel line. Once I saw this number I dug an old pressure regulator out and stuck it inline and dialed it back to 1.5 on the regulator but it still showing around 3psi on the gauge so not sure how effective the regulator is BUT the motor seems happier! AFR is all over the place at idle but in the 11-12 range now and gets leaner at higher rpm! So do you guys think we are on to something here?

 

I had to leave it there for today. I am going to double check float levels next, I’d measured 23/24mm using the zip tie method through the e tube but is go8ngvto pull the tops off and check them again. Any thoughts on gong to 175 on the needles while I’m in there? I’m at 200 now

 

@Son of Marty cold start has been eliminated

 

 

Edited May 4, 2020 by ibewebbman
clarity around progression holes

[Chris_B]

3 hours ago, ibewebbman said:

1. After inspecting the progression holes I found that indeed I had something hanging up - thanks @TobyB ! I disconnected all the linkage and removed the idle speed screws completely. I now have one of the 3 holes covered with everything just sitting there disconnected. Is this right?

No, this is not right. With the linkage disconnected and idle speed screws back off, you should see all 4 of the first progression holes mostly covered. Possible causes of this include (i) bent throttle shafts, (ii) nuts on throttle shafts too tight (although this would not explain why you can see the throttle plate on one side of the carb but not the other) and (iii) throttle plates not correctly mounted on the throttle shaft. 

 

Pardon my ignorance for not having followed this thread very carefully, but do you have brass or steel throttle shafts? It is possible that someone was messing with your throttle plates? You may want to call Carbs Only and see what they think about your throttle plate positioning. 

Edited May 4, 2020 by Chris_B
poor grammer

[Hans]

I would hold off fiddling with jets until you finish dealing with the shopping list above.

[ibewebbman]

@ Chris_b and @ Hans - sorry that was not clear on progression holes - I have 3 progression holes per barrel - the first one is covered and this is consistent across all 4 barrels of both carbs - sorry for the poor choice or verbiage describing this initially.

 

[TobyB]

I have to admit, I did a facepalm when I saw SoM's post- the warm- up circuit really does deliver about a 10:1 mix...

 

Quote

 I now have one of the 3 holes covered with everything just sitting there disconnected. Is this right?

 

IF the next two holes then get covered, and subsequently uncovered, as the throttle opens, that's about right.

In fact, it might be a little too closed.  Thus, you can use the idle screws to open the throttles a little bit until

the plate JUST starts to uncover the first hole.  Then close it again, and see if you can get it to idle.

 

However, if 2 of 3 are already uncovered, nope, that's way too far open. 

Why? oog, now we are into the 'Webers are a pain'

department.  I start to run out of ideas at this point...

 

As far as fuel pressure-  dial it down to 1.5 psi just to rule it out for idle tuning.

 

You're making progress.  Keep at it!

 

t

 

edit- we were typing at the same time.  The mechanical sync across your carbs is good, as

the holes show.  If the next 2 holes get covered, then uncovered, you're on the right track.

 

Edited May 4, 2020 by TobyB

[halboyles]

On 5/2/2020 at 1:51 PM, 2002Scoob said:

This can be done by shining a flashlight down the throat of the carb and looking at the little circles of light exposed. 

 

Seems like there is a little confusion about what "closed" progression holes actually means.  If the butterflies are completely closed, especially with all linkage removed, all of the holes (whether 2 or 3 or 4, ...) should be visible on the air filter side of the butterflies.  After synchronization/idle settings are completed, the edge of the butterflies might just be visible on the edge of the hole closest to the manifold.  Using the flashlight trick with new 45 DCOE 152's, the first pic shows the butterflies completely closed and all three holes illuminated.  The second pic shows the edge of the butterfly just peeking into the first hole toward the manifolds with the idle adjustment screw barely turned against the tab on the throttle lever.

 

[TobyB]

Ah, yeah, Hal, you're right-

 

but on some carbs, the plate covers the hole closest to the plate.

I've been messing with 45's most recently, so this might be my memory leaking...

 

t

 

[halboyles]

1 hour ago, TobyB said:

so this might be my memory leaking...

 

I don't know about you, but I have a memory like a steel whatcha-ma-call-it.

 

But now that you mention it, I seem to recall some DCOEs where that first hole is blocked with the butterflies completely closed.  Great, now that means I've got to dig through my carb boxes to find an example.  Another perfectly good social distancing day wasted on '02 trivia!

[Preyupy]

The other possibility is if the idle mixture screws are turned in and TIGHTENED too much it will actually brake the casting and the holes will no longer be round and the correct size.  It is uncommon for them all to be damaged but it is something to look at.  

 

Again make sure that the pistons in the cold start circuit are closed.

[Hans]

42 minutes ago, Preyupy said:

The other possibility is if the idle mixture screws are turned in and TIGHTENED too much it will actually brake the casting and the holes will no longer be round and the correct size.  It is uncommon for them all to be damaged but it is something to look at.  

 

Again make sure that the pistons in the cold start circuit are closed.

I know of one such case. Had to buy a new body. But lets not panic quite yet. Where are we at, anyway?

[ibewebbman]

Update - I did not have much time today but I did check and adjust the floats - these carbs are series 8 which I think originally came with brass floats. I saw somewhere the float attachment to the carb top plate on the brass floats version is longer than the top plate that originally came with plastic and now that I have plastic floats that needs to be compensated for a bit. Lots of conflicting info on this subject - measurement location etc - even weber authored info seems to conflict often...

 

The front carb was set a bit high either way so I lowered it a bit to 14/25mm ( I was at 12 and I think that may be correct for the newer plastic float carb top version?) measured from the front of the float to top of carb body with gasket. I was getting some weeping at the inlet fuel filter on this carb so I hope this clears that up. The rear I have not had this problem with since I set the floats last but I checked it anyway and made a smaller adjustment. They match now at least

 

I also played with the linkage a bit more and hopefully improved it. Knowing I will need a long term fuel pressure solution I ordered a filter king / malpassi unit but that wont keep me from making progress.

 

I should be able to start the car tomorrow and will report back.

 

Again many thanks to all of you for your thoughtful help!

 

Alex