Re-jetting (or not) the DFEV

[wetminkey]

The "flow" occurs when I would expect to see a "squirt" with all of my other carbs. I had noticed it long ago (and forgot about it, too), but only questioned the discrepancy today. I would then suspect a damaged accelerator pump diaphragm,...
Brand new, Spanish-made, Redline Weber DFEV in the box with paperwork,...I'm NOT impressed.
BTW DFEV jets are:
Idle 60 50
Main 137 140
Air Correction 165 160
Emulsion tubes F66 F50
In comparison, I see that the old ADHA had +10 air correction jets and -15 main jets,...which makes sense.
Thanks, dinghyguy, I believe that you refer to the "Carburetor jetting help" thread,...I'm watching it!
Thanks, guys. Wish me luck!

[18Fiatsandcounting]

The jets you listed are appropriate for this carb on a 2L engine, so I don't think your engine reving issue is caused by the wrong jets. Many things don't add up from what you've told us about this carb, and so at this point, I would recommend finding someone in your area who knows Weber carbs. Even if you hand them just the carb (removed from the engine), they should be able to take a look and see what's going on.

-Bryan

[wetminkey]

Gosh, Bryan, always the jokester,...you make me laugh!
There is NO ONE in this area that knows ANYTHING about Weber carbs, let alone carburetors, in general. If I knew of anyone, I would have consulted them already,...I'd have to ship it to someone.
Anymore, most people that know anything about carburetors are dead,...just kidding.
Looks like the carb settings, that I made the other day, are Within Normal Limits,...so, I think it's idling OK.
I want to eyeball the accel. pump diaphragm. And then I want to pull the new plugs and check 'em for color, etc,...
I see that the carb that they are dealing with on Mirafiori is a DFEV,...I'll be watching that thread, too.

[18Fiatsandcounting]

Sorry, didn't mean to be humorous, and yes, I do tend to kid around.

But seriously, I was thinking there must be a shop in Ft. Collins or the like who knows Weber carbs as they're not that uncommon. And certainly Denver, although that might be a stretch to take your carb all the way down there. Lots of speed shops use Webers, even if they are for another car brand (Datsun, BMV, MG, Alfa, hopped up Fords and Chevys, etc).

As you've tried so many different approaches, I keep coming back to the thought that either something is missing from this carb, or it has an internal "flaw". By the way, if you see fuel coming into the barrel when you work the throttle, that tells me that the accelerator pump diaphragm is functional. There might be another problem though, such as the gaskets around the accelerator pump jet (where it sticks out into the barrels) are missing. That could cause fuel to dribble out from the sides of the jet rather than squirting into the middle of the barrel as it should.

At this point, I'm pretty much out of ideas.

-Bryan

[dinghyguy]

on my 32 adf there is a check valve consisting of a small ball, in a closed vertical passage between the float bowl and the accel pump chamber. The purpose is to prevent backflow into the float bowl when the accel pump was pumped. On one carb the ball was stuck, the result was a dribble not a jet into the barrel. It took me a bit to figure out the problem. The closed passage was accessed by pulling out a brass plug between the two chambers which was set flush with the top of the bottom casting.
Assuming you have something similar I suggest taking the carb off the car and in a very quiet place shake the carb and see if you can hear the clink of the ball. If the ball is stuck you may need to drill and tap a screw into the brass plug to enable plug removal, then get the ball out and loose. However before that i would start with a very thin wire and see if you can feel the ball move or some low pressure air or some carb cleaner or all of the above.

If the ball check is ok,
if the accel diaphragm works and fuel squirts out,
if the jets match other peoples jetting for the same application,
if all the passages are clear,
if there are no vacuum leaks and
the float is set right
then
take it off, find a fiat friend in Denver, take the carb to him and try it on his car. (You could mail it to me or Bryan but that would cost too much)

cheers
dinghyguy

[18Fiatsandcounting]

Good point Dinghyguy, I had forgotten about that check valve. One check before you get to the point of trying to remove the carb is to remove the top cover, make sure there's fuel in the bowl, and remove the accelerator pump jet (held with a flat blade screw in the middle). If you (well, Todd) work the throttle, fuel should bubble up from the accelerator well in the center of the carb.

But I'm thinking: If the accelerator pump doesn't work, that would cause a flat spot upon acceleration, but if the engine won't rev past 2000 rpm or so, that sure sounds to me like either a major vacuum leak or the main jet circuits are not working*. Around 2000 rpm and up, you should be able to see fuel spraying from the middle of the auxiliary venturi (not the main venturi, rather the round tube in the center of the barrel with the "wings" on either side which secure it in the center of the main venturi).

*or a problem with compression, cam or ignition timing

-Bryan

[wetminkey]

see March 9 1145 post,...good compression test, timing marks/rotor set + new belt. You forgot,...
Starts right up. Ran it today and I was wrong,...I can see a nice stream from the jet on the primary side,...no dribble or gush.
All is as it should be,...except the car only idles. On slow acceleration it bogs at about 1500 and tries to die. Has to be jetting.
What a POS carburetor,...even my VW's friggin Solex 34 PICT 3 one barrel runs better than this! I can see why Redline's reputation is so poor,...Weber used to have a REALLY good reputation!
Fellow on mirafiori has the same kind of problems with his DFEV,...but Brad Artigue has just provided some DHS jetting info,...
BTW, ALL of the DFEVs came with the same jetting, despite specific car/truck applications. That's why I'm a little hesitant to start changing the jetting,...
And unless I can find real problem with a brand-new carb, it would be pretty stupid to send it out for repair.

[18Fiatsandcounting]

I'm out of ideas, and I hope that someone else can recognize these symptoms and help you get your spider back on the road.

-Bryan

[SteinOnkel]

see March 9 1145 post,...good compression test, timing marks/rotor set + new belt. You forgot,...
Starts right up. Ran it today and I was wrong,...I can see a nice stream from the jet on the primary side,...no dribble or gush.
All is as it should be,...except the car only idles. On slow acceleration it bogs at about 1500 and tries to die. Has to be jetting.
What a POS carburetor,...even my VW's friggin Solex 34 PICT 3 one barrel runs better than this! I can see why Redline's reputation is so poor,...Weber used to have a REALLY good reputation!
Fellow on mirafiori has the same kind of problems with his DFEV,...but Brad Artigue has just provided some DHS jetting info,...
BTW, ALL of the DFEVs came with the same jetting, despite specific car/truck applications. That's why I'm a little hesitant to start changing the jetting,...
And unless I can find real problem with a brand-new carb, it would be pretty stupid to send it out for repair.

Not surprising, that Solex is a wonderful carburetor.

It is my understanding that all the DFEVs come with the same jetting from Redline.

I highly doubt you have a jetting issue unless you are a) way off base with the idle jet or b) there is something physically wrong with the idle jet you have.

Much more likely I think are improperly machined passages inside the carburetor. The only way to check that is to get the carburetor flow tested or bolt it onto another engine and see what it does there or strap a different carburetor onto your engine.

Other than that, I'm also out of ideas.

Cheers
Steiny

[geospider]

For fun, have you tried setting the float to allow more fuel in and maintain a little higher level.
when mine was too high, it ran great, just was pouring fuel in. But you will know at lease if you are now running your bowl out of gas. When mine was set too low (yes, I have been on both sides of this float adjustment thing) mine did somewhat as yours: would bog down shifting into 3rd, wait off throttle then slowly go again. Every time.

again, gotta try something.
to quote a great carb guy out my way: you set the float to where YOUR car runs best, same with the jetting.

[wetminkey]

I've set the float at each and every recommended setting that I have found, and none make a difference.
Most recently, Weber Redline recommends an 18mm 'upper' float setting and a 2mm drop at the needle valve for the 'lower' float setting. But I've seen at least two different pairs of upper and lower settings - they all can't be correct.
Engine is not starving for fuel, it loses rpm with more throttle after about 1500 rpm.
I'm tearing the brand new carb apart,...It's time for a 'cleaning and rebuild' process, just like I would do on any dirty carb,...
Wish I could throw the ADHA on the single-plane manifold to test and tune,...that would be too easy.

[SteinOnkel]

I've set the float at each and every recommended setting that I have found, and none make a difference.
Most recently, Weber Redline recommends an 18mm 'upper' float setting and a 2mm drop at the needle valve for the 'lower' float setting. But I've seen at least two different pairs of upper and lower settings - they all can't be correct.
Engine is not starving for fuel, it loses rpm with more throttle after about 1500 rpm.
I'm tearing the brand new carb apart,...It's time for a 'cleaning and rebuild' process, just like I would do on any dirty carb,...
Wish I could throw the ADHA on the single-plane manifold to test and tune,...that would be too easy.

I already offered to send you my spare adf to bolt on and try months ago

[wetminkey]

Somewhere, I must've missed THAT! COOL!
I've been trying to email all the nearby Spider folks I know, to see if they have a carb that I can use, with no success,...so I really appreciate your mentioning it again!
Let's go to Private Messaging here,...you've got one in your box.
Thanks again, man!

[wetminkey]

Well that was not an option,...

Just because, here is the Weber 32/36 DFEV body torn down:


Primary circuit is on choke side. Idle jets are out of their holders,...
Found the "brand-new" carb to have some grit and flecks of black garbage on the business-side of the strainer, in the bottom of the bowl, and in the accel. pump reservoir,...strainer was clean. The black garbage seems to be a "sealant" (or something?) from the edge of the copper washer on the full power needle valve at the bottom of the bowl. I've polished it clean and I'll flush the carb body thoroughly with a syringe and laquer thinner. I also found a spotty corrosion on the top gasket surface of the body, and wire-brushed it away.
Just to verify: I assume that the accelerator pump nozzle ONLY pumps fuel to the primary throttle bore (two horns on the nozzle, but only one has a hole),...
Oh,...and there are THREE adjustments on the DFEV,...idle screw, mixture screw, and fast idle set screw. I know that the mixture screw is set at about 2 turns out,...idle screw is set to less than 1.5 turns in, from contact,...WHAT is the setting for the fast idle set screw?
"Tune up kit" from piercemanifolds.com is on it's way (it has top gasket and both diaphragms (accel. pump and power valve)),...
I'll attempt a high altitude change to idle jets and air correction jets and see what happens,...wish me luck!
Thanks, Todd.

[wetminkey]

Interesting that this DFEV is stamped as a DFAV on the base,...