I hope you only used one of the washers under the float valve. There are 3 different thickness washers so you can set the height of the float valve. All 3 would be WAYYY too high.
Misky;
The Buckeye Triumph club has a web site and it has a great write up on Z-S carbs, basically the same that we have on our S 2 Jags.
https://www.buckeyetriumphs.org/carburetors
On page 9 of the first part of their write up it discusses your leak (I think) . These articles are printable.
Regards, Joel.
Doug, thank you for clarifying. Yes, I only used one washer. I’m going to adjust the float height this evening. Appreciate the diagram.
Hi Joel, this is a great resource! Very, very helpful. Many thanks for sharing this! I shall give this a thorough read! Misky.
I bought a couple of the solid “foam” type floats one time rather than the original hollow type that I had found prone to leaking and sinking. Turned out that one of the pontoons on the solid type float was a little loose fit on the metal piece and could pivot a little and drag on the side of the brass plug. If you got one of those solid type ones you might check for this. Seems like if fuel is coming out of the hole you are pointing to it would be a float/bowl needle problem unless the pump is putting out too much pressure and overpowering them.
David
68 E-type FHC
Thanks David, I replaced mine recently with an upgraded nitrophyl float which is shaped like the original but apparently more leak proof (as my earlier float had absorbed fuel). I’m going to double check the float height as other members on this forum have rightly suggested and then see if my fuel pump stops continuously ticking. I’m hoping the continuous tick will disappear once I’ve sorted this and that it is not the pump! Looking to provide an update.
I just finished dealing with this problem (twice!).
The rear carb was leaking out of the same hole as yours. I changed the needle valves and floats on both carbs. The rear had a float with fuel entrapped inside despite being an “unsinkable” nitrophyl float.
The front had no apparent issues but since they were off I decided to change out the needle valve and float. I carefully set the float level on both to match the recommended height.
After remounting the carbs I found fuel coming out of the same hole but now from the front carb!
I removed the carbs, took off the float bowl on the offending carb and hooked it back up to the fuel system while holding the carb upside down. I found that fuel was leaking around the washer at the base of the new needle valve.
Tightening the valve solved the problem.
I have video if you you’d like to see it.
Good luck Bill
Thanks Bill, seems to be a common issue! I’ve understood. I’ll certainly check up on the needle valve washer now that you’ve warned me. Its good to know this as a minor detail overlooked could mean an unresolved leak! Appreciated…
Worth noting that the drawing for setting the float ‘height’ says ‘carburetor inverted’ - in other words, the usual method is to have the carb on the bench upside down and the float at rest against the (closed) valve. It is possible to simulate that position with the card installed but care must be taken and the setting likely to be less precise.
As suggested, use the washer that gets you closest to spec and bend the tab for the final setting.
Well rats I did not know that fuel could get inside the nitrophyl floats. One more thing to worry about but good to know if fuel starts coming out of that overflow hole again. It has been several years since I had any of these kind of problems though. Right now I think I have nitrophyl in one carb and hollow in the other. Wonder which one will sink first ?
David
68 E-type FHC
Would that not be WAYYYY too low?
1 Like
Not with the carb upside down 
Thanks David, Yes, apparently the nitrophyl floats are “supposed” to be leak proof. I quite like the original floats. They seem to be much better made for the time and lasted quite long. I’m stuck at the moment as in a bid to address the carbs I toyed with changing the metering needle and it is stuck in the piston so tight that it seems it is welded in there. To make it worse the spring unit within the needle pulled out leaving the casing in there and now it seems just impossible to get out without having any grip!
Years ago I too messed up my fixed needle trying to get it loose of the piston. I was able to eventually get it all out even though I had mangled the needle. If you get stuck you might check with Joe Curto. In 2015 I wanted to switch over the the adjustable type piston and needles like are in the later ZS carbs. He sold them to me then for $137 total for both sets so I could just attach the diaphragms and drop them into my carbs. I like them much better than the fixed needles. He also has adjustable jets for them and I think this is the way most folks go if they want to be able to play around with the mixture.
David
68 E-type FHC
Thanks for sharing that information David. If I have no luck with getting out my metering needle (Doug had warned me about this) I’ll have to find a replacement piston or contact Joe Curto. Good to know there is someone experienced in this niche!!
Hi Joel,
I managed to fix the leak! Many thanks for your help and information. Changing the needle valve and the rubber diaphragm (the culprit) solved the issue. That said, I’m trying to tune the carbs and while I have not altered the current jet adjustments (as I am a novice) I did try to play with the idle stop screw as the carbs seemed to be running lean. As I increased the speed though the rpms also rose and the car seems comfortable idling at 1500rpm which seems high given the automatic idle is supposed to be around 650-700rpm (is this so?). Also, my rear (fixed) carb seems to be showing a very low reading on the unyson. Can you tell me where I might be erring or direct me to a simple step by step way to do the tuning? Much appreciated.
Misky
Misky;
Make sure the diaphragm of the front carb is OK. Set the carbs to the basic setting and follow the book as the adjustment, recheck after each setting change.
John Twist of ‘University Motors Ltd.’ (now closed but You Tube videos are up) has a 3 part video series on the Z-S carb that might be of help.
Regards, Joel.
Thanks Joel,
I believe the video you’ve linked is specifically for cleaning and calibrating a ZS 150 choke. I’ve looked to see if there are any videos for tuning the ZS 175CD-2 carbs and cannot seem to find any. That said, I’ll take up your advice on how to set up the carbs and check the diaphragm on the front carb (not leaking). In the meantime, if you come across any other information I’d be obliged.
Misky
Misky;
I just looked at the videos and indeed they are not what you are looking for, sorry for the wild goose chase!
Joel.
Not at all Sir! I appreciate your sentiment and willingness to help. Best to you!