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Discussion Starter #1
Well, I rebuilt 3 of these carbs on my 2600 and didn't have an issue. Just rebuilt the 2 carbs on my 2000, and after an initial nice smooth idle, the front carb started leaking fuel out of the primary barrel. I checked the float level and verified complete fuel shutoff with the brand new needles. All of the jets are tight, as is the atomizer inside the barrel. After reassembly and further idling (doesn't leak for the first few minutes) it also started to puddle fuel in the secondary barrel.

This may have been happening before the rebuild, as the front carb was overfueling (front 2 plugs very black) but now I have the log plenum off so I can see it. Rear carb is great, no leaks. I did notice when I took the main jets out to rebuilt it, they were stuck on old O rings inside. According to the diagrams, there should not be an O ring on these, just the phenolic washer. Could this be an issue? Help!
 

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I think the notion that fuel pressure may be too high makes sense.

I cannot contribute much to the O-ring vs. phenolic washer discussion.
 

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The PHH44s dribble, and being placed flat rather than inclined, they dribble out the intake. Of course, there's a quantity that would indicate a problem, but the reason your right-side structure under the plenum usually develops rust is that lifetime of fuel drops that eventually work through the paint and expose unprotected steel.
 

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float needles need replacement maybe.?
 

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float needle seats may be defective maybe ? on older carbs with brass floats fuel might have gotten in through degraded solder joints.
 

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Discussion Starter #7
Float needles are new, verified that they work, and the float level is perfect. It makes sense that fuel pressure would flood the front carb first, but the float bowl fuel level would be too high (and it is bang on spec). It seems like the fuel may be coming from the accelerator pump nozzle, but is that the same place the float bowl overflows? Again, this is the front carb only, rear one stays dry.

I did find that I had the main air rectifier jets switched between barrels, so I corrected that in both carbs but I am at a loss here. I'll try to post a picture of how much it is dribbling... it is more than i would expect.
 

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Discussion Starter #8
Update... removed both carbs. Rear carb was dry in the accelerator pump, wasn't getting fuel from the float bowl. After removing the obstruction and verifying all else, I reinstalled them. It still dribbles fuel from the front carb, but also now dribbles a tiny amount from the rear, nowhere near as much as the front. It does run WAAAY better than it ever has now. Before, I don't think the secondaries were opening at all, and now it pulls smooth and strong right to redline. There is still a slight miss at light cruise, just off idle that smooths out with a little throttle.

For some reason, after setting the idle, rev the throttle, it never comes back to the original idle. I find I can push the secondaries shut (staying slightly open after throttle application) then the idle comes back down. What causes the secondaries to stick slightly open?
 

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I can sympathize with your plight. Same problem on my recently recommissioned 2000. Rebuilt the carbs off a 45K mile original car. Fuel dumping out the front carb (mine was the floats..I found an old PHH44 manual that showed a different way to set the floats and it seemed to work). BTW, my carbs don't dribble anymore - there is also a small brass nipple fitted on the bottom of the carbs near the opening that attaches to a hose that leads down to a tab on the oil pan that directs the fuel onto the ground. This is supposed to be the path of any overflow Anyway, once the float level was solved, getting consistent idle is now the deal. It idles but it never really settles at the same place.
A couple of things are helping with idle quality. First, if you get to the point of taking off the carbs again, look very closely at the edges of the butterflies. Even very slight imperfections (a small nick or bump along the edge) can vary the idle as it never 100% seats the same from each open to close. This goes the same for the seating surface inside the carb barrel.
Second, using the car helped. My car had been off the road since 1974 and the "stops" on any of the moving parts are getting resettled in.
I'm not sure the PHH44's are worth it in the end. Original yes, but lots of trouble and "expertise" is expensive and scarce. If i had to do it all over again I'd probably pick up a Weber intake and some 40 dcoe's. Car would have been on the road months sooner with far less aggravation I think.
 

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For some, pure originality is paramount. For others, it is the joy of the experience. The former tend not to drive their cars much. For the latter? Put the Solexes in a box, and do the full Weber conversion. The path is now well defined, and you’ll no longer dread the idea of how your car is going to behave during a sudden impulse to take it out for a drive.
 

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I had the same problem as you describe with my Solex. You couldn't just pull away gently, I had to rev it to 1500rpm, at slow speed it would splutter to a point where it was un drivable then spill fuel all over the road. In my case the fix was simple. I took the new idle jets out and soaked them in carb cleaner over night, the amount of tiny bits of brass swarf in the bottom of the cup the next day was astonishing. Now she starts first time....usually, pulls away just off the clutch smoothly and is a pure joy to drive. Hope yours is as easy a fix as mine.
 

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Discussion Starter #12
Losing my mind on this. Just swapped the float needle with the old original, still the same. I read somewhere that the aftermarket needles aren't good and can't take the pressure that originals can. I also saw a youtube video about these carbs on a 190SL site where the accelerator pump check valves can stick and cause overflow as well. Ordered 2 new ones. I'm hoping there isn't some kind of a hairline crack that is opening up when warm. It idles fine for like 3-4 minutes, then starts dripping.
 

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Losing my mind on this. Just swapped the float needle with the old original, still the same. I read somewhere that the aftermarket needles aren't good and can't take the pressure that originals can. I also saw a youtube video about these carbs on a 190SL site where the accelerator pump check valves can stick and cause overflow as well. Ordered 2 new ones. I'm hoping there isn't some kind of a hairline crack that is opening up when warm. It idles fine for like 3-4 minutes, then starts dripping.
i was going to suggest that.
 

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This will not help but it is true these carbs will leak some fuel , that is why they have the drain pipes underneath. I lived with the leaks until I replaced with Dellortos. Getting through the channel tunnel ( UK to France) was difficult as the smell of petrol would set -off the fire detection system in the train. Which then had to be turned off in the carriage the 2600 was in and we then had to travel with our own personal fire marshall.
 

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I had a similar problem with fuel leakage on the Solex pair. I checked the floats and valves and found nothing wrong. Than re-assembled and and decided to mount the air intake and stabilizer bar to the carbs. The leaks eventually stopped. Maybe the stabilizer corrected the carburetors to the proper level. I restored a190SL awhile back with the Solexs and once dialed in they were no problem.
As for an unstable idle, it could also be a sloppy, worn, sticky Marelli distributor. They can be very finicky at times.
 

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Discussion Starter #17
What kind of fuel pressure is correct for these carbs? I seem to recall that Webers are very sensitive to fuel pressure and like very low pressure. I just put a gauge on my car, and once the float bowls fill, it pegs at 7psi. Shouldn't it be closer to 3-4? Could the pressure be overwhelming the needle seats?
 

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Whoa... 7 psi is too high for pretty much all float-type carburetors. Have you recently installed a new pump, or a different spring in your existing pump?
 

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Yep - That could be your problem - although you need a high fuel delivery rate the pressure needs to be low . This debated in many posts on Alfabb and I believe should be less than 3 psi . I have fitted a filterking on my car to limit pressure

An example

"I have a 1972 factory technical specifications manual for the 2000 series. These were factory fitted with Solex DDH or Dellorto DHLA carburators - Webers came later on 2000s.

This manual specifies the fuel level setting instructions for both types of carburetors. Both pages ask to set the float level with a feed pressure of "2 meters water". 2000 mm H20 converts to 2,9 psi."


Google search "alfabb fuel pressure solex" and you will find more
 

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What kind of fuel pressure is correct for these carbs? I seem to recall that Webers are very sensitive to fuel pressure and like very low pressure. I just put a gauge on my car, and once the float bowls fill, it pegs at 7psi. Shouldn't it be closer to 3-4? Could the pressure be overwhelming the needle seats?
I'm glad you're starting to wake up to what was written in post #2 and #3 above -- 11 days ago.
 
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