Carb pedestal leak

[phils114]

Hi All,

Been having some poor idling and running issues lately, so decided to play around with the carbs. After a few replacements and adjustments, I was still seeing problems. After looking at many previous posts, I decided to look for air leaks. After spraying some carb cleaner around the pedestal area, there was a definite increase in engine speed. I replaced the o-ring, but still getting the same problem. I’m not sure that this o-ring is even doing anything as the carb mounting feels like it is not sitting flat on the manifold , even if take it out.
Assuming one of the surfaces is not quite flat, can anyone recommend a sealant that will solve the issue, or is there another course of action I can take?

Many thanks

Phil

[jbuckl]

Check the thermac one way valve pipe before using sealant.

Check the nut & stud is sound & not bottoming out.

The boss thread in the manifold is often damaged.

Have seen a few where the nut is tightish but pedestal is not clamped down.

[phils114]

Thanks for the info. I’ll check these tomorrow

[RNF]

Hi All,

Been having some poor idling and running issues lately, so decided to play around with the carbs. After a few replacements and adjustments, I was still seeing problems. After looking at many previous posts, I decided to look for air leaks. After spraying some carb cleaner around the pedestal area, there was a definite increase in engine speed. I replaced the o-ring, but still getting the same problem. I’m not sure that this o-ring is even doing anything as the carb mounting feels like it is not sitting flat on the manifold , even if take it out.
Assuming one of the surfaces is not quite flat, can anyone recommend a sealant that will solve the issue, or is there another course of action I can take?

Many thanks

Phil

I had a similar issue and it turned out that the threads in the manifold gave out, so the post was stripped. IMG_0830.jpg

Simple fix of putting in a helicoil.

[DJT]

There is a roll pin which stops the carb pedestal from turning on the manifold. Make sure the pedestal is not fouling on it

IMG_0084.jpg

[Goldstar]

Thanks for the info. I’ll check these tomorrow

I had to put a new thread into my manifold stud “hole” using a helicoil (I think it was 3/8”)

I also had a pedestal leak and having made sure the exit to the air filter was blocked off and using Hylomar sealant on the pedestal, I still had an air leak.

Turned out that the spindle shaft seals were old a crusty and not sealing so air was getting in past the spindle that the butterfly valve sits on. The temperature compensators were also badly set so further weakening the mixture.

[jbuckl]

Confession time …. My first stag was supposed to be a daily driver.
1st night in Birmingham for a new job, the stag failed to restart.

Upon someone leaning on the air filter, it did start!

it was a stripped pedestal stud.

temporary fix was a folded piece of carpet on the air filter & slam the bonnet shut! Worked!

[richardthestag]

I just wonder how many folk have sought out alternative solutions when it was simply an air leak on the inlet side of the carb needles.

I helped a mate and thoroughly good chap Goldstar rebuild a pair of strommies for his stag. turned out that all they needed was new throttle spindle seals and to get the temp compensators to not be wide open at ambient 17c temperatures. After an aborted restart due to a used old stock float valve failure. Order was resumed and the car was instantly improved despite still needing a fine tune and balance.

I got into this because even family fun garage businesses were not interested in anything that couldn't be "fixed"* by computer.

[phils114]

Thanks for all of the input.
so, the latest is, I have checked the pedestal stud, and that is ok, with plenty of thread. The roll pin is not fouling the base.
I have disconnected thermac valve and blocked it off.
What I did find though was that I had a sealing washer missing from the nut and spring washer that holds the pedestal down. This has definitely helped with the air leak, and so far the engine is idling a bit better.
I still need to check the spindles and butterflies, but I’ll settle for this now, so at least I can get out on a long run to fully test it

Thanks again

Phil

[jbuckl]

Spindle seals are separately available from chris witor.
Otherwise , you have to buy the complete zenith kit £££ now.

[richardthestag]

If you are careful getting the brass cup out that holds the seal in place you can remove the brittle old seal and maybe find a generic o ring that suits the shaft diameter and refit to the carb body using the original cup. Gentle use of a suitable flat blade screw driver to lever them out does work

[jbuckl]

Have not found that the cups can be reused very often…. Or is that just because I had new ones waiting, so wasn’t trying carefully enough.

[richardthestag]

Have not found that the cups can be reused very often…. Or is that just because I had new ones waiting, so wasn’t trying carefully enough.

yes but when they are a Lady (Godiva) each + the chancellors cut, you try take them out carefully.

[jbuckl]

yes but when they are a Lady (Godiva) each + the chancellors cut, you try take them out carefully.

I think a set of seals & cups is £50 now… cheaper than an alternative fuel metering system though.