weber 50DCO/SP trouble shouting

[Vagos]

Hi to all!! I wonder if anyone can help me through solve some problem with my 50dco/sp. Just to let you know, the 50s came with factory jetting, which means they are running at:

46 chokes
auxiliary venturi 5.0
main jet 180
air jet 160
emulsion tube F7
idle jet 65/F8
idle mixture orifice/bush 135
progression/transition holes 100/100/100/100
needle valve 250
pump jet 45
pump spill (relief) 100
float level 12mm

I use them with a FACET fuel pump of 5,0-6,0 psi flow rate and 27gals/hr. I have also MSD6AL ignition and MSD blaster coil. Engine is 2512cc and I suspect the cam is the culprit responsible for my trouble due to big overlap (324@duration,104 lobe center and 13mm valve lift), as the valves aren't allowing the fuel in until the engine "comes on the cam".

My problem right now is that I also use a fuel pressure regulator adjusting the pressure from 0,5-5,5 psi. When i have the engine work at 1,5 psi, it has a nice idle at 1000-1100rpm, but on the acceleration, you can realy feel that the engine needs more fuel.

At 3,0psi, the car definitely pulls much HARDER, but working at idle for about 10-15 minutes is enough to drown the spark plugs and the carbs are starting to flood. I removed the top covers and checked first to see my float levels if they are correct as WEBER manual specifies for the plastic, "Spanish-type" floats.

Mine, upside down with the the float tab just touching the needle valve, were 15mm (no gasket) versus 12mm per Weber and, on the drop position where they should be 26-27mm, mine were 33mm!! That means at least that I have less fuel inside compared to the stock set up!!

I tried something else, I put a T fuel union to the last carb to send the extra fuel all the way back to the tank. I know that Weber should work at 0,4bar (around 4,5psi i think), but 4,5psi or 5psi doesnt work for me. I found out that 3,0 seems to suit it best right now, but there is still a little tiny bit of flooding, but it holds and doesn't drown the spark plugs as before.

Have used the car in traffic, work and highway for about 60-80 miles before any signs of low power begin to appear due to wet spark plugs, but the idle is still smooth.

I wonder if anyone can give a theory of how the webers should be set up correctly. I see a LOT of German tuned cars with CIH engines using a 324 duration cam like mine and using 50 DCO/SPs without a T pipe at the end to return fuel to the tank. I am going to see a Weber specialist in the next week, but I would just love to hear some thoughts and opinions . . . .

[tekenaar]

. . . trouble shouting, I love it!

On a bit more serious note, I edited your original post a bit for readability and to help direct answers to what you're looking for . . . hope it doesn't offend!

First, a quick question . . . is this an SSD - "single carb" or DSD - "dual carbs" intake installation?

Secondly, Webers are designed to operate most efficiently at 2.5-3.5 psi fuel pressure, but require sufficient VOLUME!! to maintain float bowl fuel levels under all load conditions. What this means is that the fuel pump would ideally be located as close to and at the lowest point of the fuel tank and that the pressure line to the carb(s) is of sufficient size (large) to meet the VOLUME!! parameters (lots of flow).

Almost all fuel pumps, whether mechanical or electrical, are designed as "pressure" pumps, not "suction-pressure" pumps . . . the distinction being that the location of the pump relative to the fuel tank becomes a chief design concern and is very important. The pump's fuel source should never be restricted in any way so that any possibility of "suction" is avoided at the pump's intake side!

[Vagos]

First sorry for my bad englishAs the years go by unfortunaly they are starting to fade away in my mind.It is a Dual set up.I have the facet install in the engine bay,seller told me back then that it is ok to install it there.But im thinking to give it a try to relocate it back to the tank.

[tekenaar]

No need to apologize for anything you posted, perfectly understandable . . . I only edited post to give you the best direct help from everyone here.

Just wanted to add that your combination of very large carbs and "race-spec" cam may not give you the ideal results expected for the particular use of the car . . . i.e. "race engine" in "street/daily use" car.

[bigjim5551212]

No more than 3.5 psi.