series 2 idle carb problems

[turbinepete]

As part of the rebuild of my car, I redid the carbs with a kit from VB.

The engine starts well but the idle is inexistant. I keep the engine alive with fuel from the acc pump by giving it gas when it`s about to die. At high RPM`s, it runs quite well.

What I think is happening is that I am pulling air at the gasket. The wall where the idle fuel passages are is quite thin and that`s why I think I have my problem. I was thinking of applying a little bit of sealube (which is used in aircraft and does not dissolve in fuel) to keep the air from being sucked in.

Anybody care to comment?

 

[Alpine Bob]

A nice Weber solved all those problems for our Series II.

 

[skywords]

As part of the rebuild of my car, I redid the carbs with a kit from VB.

The engine starts well but the idle is inexistant. I keep the engine alive with fuel from the acc pump by giving it gas when it`s about to die. At high RPM`s, it runs quite well.

What I think is happening is that I am pulling air at the gasket. The wall where the idle fuel passages are is quite thin and that`s why I think I have my problem. I was thinking of applying a little bit of sealube (which is used in aircraft and does not dissolve in fuel) to keep the air from being sucked in.

Anybody care to comment?

Hello Pete
I assume you are talking about the infamous Zeniths? I think they stumbled right off idle when new. The sealube is a good idea and should be used sparingly on all the sealing surfaces. It was called Fuelube not to long ago and it is great stuff, I use it on some engine gaskets as well if I want to reuse a gasket later such as rocker box. I have found a simalar substance on gaskets on my cars that I think came from assembly at the Rootes factory, a none drying paste of about the same consistancy. The Brits probably have there own form of Peanut butter, maybe Nick can remember what theirs is called.

I have found it helpful to run my idles on the high side at about 900 to 1000 rpm. I will probably be scolded for doing it but the carbs behave themselves better at those idles. A warm up before driving is most benificial to their performance, they are cold blooded.

 

[husky drvr]

> Ignition and valves must be properly adjusted and working.

> Make sure the lower throttle section of the carb is tight to the body.

> Check for worn shafts that would allow air to leak by at idle.

> Make sure carbs are synchronized for air flow.

> Idle speed about 800+/- 50 rpm approx. on a hot engine.

> Keep in mind that these carbs are set up to just off a rich idle condition not at the best idle possible.


Just a few more thoughts,

 

[bkasl]

What style of Weber and manifold did you use, I have a S2 with twin Zenith and have often considered the Weber conversion. 40? Brent

 

[sunbeam74]

Carb issues

Brent,

It sounds like you have a air leak. Unfortunately, the carb base and faces have a tendency to warp. When apart it is good to take a fine sheet of wet/dry paper on a flat surface (make sure it is flat) and "face" the carb surface.

You know, I am looking at a direct replacement for the Zenith. The Weber 34 ICH (ICT) mates up to the stock manifold. The catch is the linkage. I am not sure if the 34's will work but it looks promissing.

Here's the benefit if it can be worked out:
1) Carbs are relatively inexpensive - less than $150/each.
2) jetting is available
3) should flow better than the DGV.

Looks "near" stock. The ICT version doesn't have a choke the ICH does.
If it did work out then for around $350 you could have virtually new Zenith like performance - possibly better than the DGV. Keep in mind the 34's were more economy oriented but I am hopeful.

Steve

 

[turbinepete]

I applied a light coat of sealube to my carb gaskets and my idle is now fine. Great stuff this sealube.