Initial carburetor setting

[keitho64]

I have been troubleshooting fuel delivery problems (popping out the intake and exhaust) and have a question.

What is a good rule of thumb for initial settings on the air bleed screws and idle mixture screws?

I have one document that references the air bleeds should start a 1/8 turn out from stop and the idle mixture at 1 1/2 turns out from stop.

Do these sound like a good staring point?

Engine in question is a 2.2T with Webers.

Keith

[Formerly Steve Wilkinson]

For what it's worth, which may be nothing, since they're somewhat different carbs and certainly a dfferent engine, the 46mm PMOs on my 3.4-liter SC have an initial pre-tuning setting of two turns out on the idle-mixture screws and all the air screws closed. You tune at 1,200 rpm with the carb-actuating rod detached from the carbs on the right side afer matching the 1200-rpm-idle airflow.

Stephan

[keitho64]

Stephan

That actually makes perfect sense to me. When I was checking them last night I noticed the air bleeds were 2 1/2 turns out. I put the idle screws at 1 1/2 out from stop and the air bleeds 1/8 turn from stop. Since I completed this at 1:00 am and my kids were asleep I did not fire it up yet. Also, I cleaned out the passages with carb cleaner so I think I am on the road to recovery.

Thanks again for the reference.

[steveW]

What a good thread. I've got the same problem on my '71 T at a fast idle it goes poof bang etc. The problem was worse, but not even a new manifold gaskets, carb clean etc cured the problem much. The carbs were full of 'sludge'.

Also my CDS unit died and replacing it with a recon unit improved matters slightly.

My car is stock and is very heavy on fuel and has a flat spot if I need to accelerate after holding a part throttle at about 4500 rpm - it almost seems to initially decelerate when I floor it from there.

Any hints are welcome.

[dhaines]

I start about 1 1/2 turns out for the mixture, all the way in for the air volume. Then, using a carb sync, open each volume screw to match the intake with the highest flow. This should get you close...

[keitho64]

Stevew

I would look into your accelerator pump adjustment. I have a document that describes how to do that if you need it. You can also search on the tech board and find it there.

Have you readjusted the carbs after installing the gaskets? If so, I would be curious how your adjustments are. My motor is a 70 2.2T which is stock with the exception of the Webers.

[TimT]

besides making sure your carbs are clean and adjusted, Its a miracle how many carb problems have been solved by optimising the ignition...

BTDT

[john walker's workshop]

lots of weber and zenith carbs still have the original .45 or .50 idle jets. they worked ok 35 years ago when the gas was good. you will never get them to quit popping or have decent acceleration if you don't open them up to at least .55 (or even .60 on larger or cammed engines). don't believe the number stamped on the jet. use a jet gauge. many have been drilled.

[steveW]

John, that makes a lot of sense, especially since we do have rather crappy fuel in South Africa, although the way things are going in the middle-east I think I'll just be grateful we've still got the damn car-juice!

[keitho64]

Quick update. I started the car up last night for the first time after making the initial settings I listed in the beginning of this post. All I can say is WOW! It runs unbelievable smooth, revs like a mother, idles as smooth as silk and no popping or anything. I cannot believe how strong and good it sounds. All 6 cylinders seem to be pulling the same amount of air so I am not going to mess with the carb adjustment until I get some miles on it. It sure seems to run strong. Before if would free rev to about 4,000 easily now it hits 6,000 without hesitation. Yee Ha!

Ah the sweet sound of a flat 6!