Help On Carbs

I just go my 512bb back from the major service. Virtually all the weak part of the 512BB have been addressed including the addition of he Newman Diff and all new SSI valves and after market AP clutch.

I decided that I may as well have the carbs done.
I am little irked because they didn't have time to install the MSD.

They don't have anyone that is really capable of tuning the carbs. So I took it upon myself to help them out. It has probably been 18 years, so I am a little rusty.

The runs OK starts good, pulls well but the idle is low @ 750 rpm. I noticed that it will load-up when you are at a stop light, the light goes green, as you pull away, the motor seems to stumble, If you use half throttle it will clear up and pull very well.

I have not adjusted the air bleeds, but have left them all the way in.
It may be on the rich side but there is not any black smoke during idle or during acceleration other than the typical with the multiple webers.

My though are that the balance of the balance of the carbs may be out because it will pop when driving at low speeds. Or maybe the original ignition is weak.

Any thoughts?

 

Thanks.

I will give it a go.

 

Thanks every one.

I decided to start from scratch and disconnect all the linkages, use the 2.5 turns, reset the butterflies to equal positions. After a few minutes it all came back to me. smooth, smooth smooth.
The results are 100% better.. The transition stumble is gone and it doesn't load up after any idling.

I do have a plug miss at 5500 rpm. I also used the factory heat range but in an NKG plug. I think I will throw in another set.

It is still a little rich, but much, much better.

The next step will be to take the float setting recommendations and follow the procedure to the 'T'. Then I will look into the jetting and emulsion tubes as Newman suggested.

In addition I have arranged to have the MSD installed.

Thanks again.

 

I can't seem to get a break.

My wife says, were is the Ferrari, how much is it costing you now, why aren't you driving it, is that the car you really wanted, one that you can't drive, blah, blah, blah

I shut the car off one day, let it sit for 30 minutes.

I went for a short drive and the car has a real bad bog. It almost seem like it is out of fuel.

I dropped it it off to the mechanic. With the help of Pierce manifolds we installed some new fuel pumps. It was real rich, so the next step was a pressure regulator.

That corrected the richness but the bog is still there.

Next step, check and replace more of the fuel lines, , check the and clean the fuel pick-up
and check the fuel pressure ( 3.5 psi)

Readjust and synch the carbs.

These carbs were rebuilt and it ran fine for at least a month.

Ran the tanks dry, new fuel, new plugs, another MSD, etc.

I had the tops removed and I noticed the the amount of fuel in each bowl was different.
All the needle valves are OK.
If you push down on the floats you will notice that the amount of fuel in the bowl will cover the tab on the floats on some but on others it is down by 5 to 8 mm.

I thought there should be more fuel in the bowls and it should be more equal.

I measured the hight of the needle valve and they vary as much as .8 mm difference.

I am leaning towards that the car is running out of fuel and the floats and needle valves are all wrong.

I requested that they be sent back to the rebuilders to recheck the carbs for the proprer settings
It has been in the shop for 2 weeks with no results.

I ma trying to help as much as I can, but I am getting fed up.

I want to drive this thing.

 

I reset the floats, they were way too high.
Not only that, from what I am reading on F Chat the jetting is all wrong on the car.

It has 185 AC jet with 135 mains. and f8 tubes., 32mm chokes.

If you drive real easy and then get into it it will leave a smoke screen.
But if you are driving on the back roads and always into it, the car runs great with very little
richness.