Zenith Stromberg Carb leaking...

[inline_eric]

Hi All,
I started my Series 5 up the other day with the hood open and noticed some light smoke coming off the motor and I was able to see something had leaked onto the exhaust and was burning off as the motor warmed up...well I turned it off and let it sit for a few days and found the exhaust to have more substance on it and looked below both my zenith carbs and there were drops off fuel...so it looks like my carbs are leaking around the jet covers (I guess) but this just started and it is both carbs...any ideas. Recent things I did were had the car tuned by a British Mechanic and also I put ATF in the Damper...is there something going on that I am not thinking about? It seems like a bad set up having fuel drip on to my exhaust..Any help would be appreciated
Eric

 

[Thor 1211]

leaking strombergs

Did he (the British mechanic) fiddle with the float levels? it's a PITA but I'd take them off and set the level. Smarter minds than mine might be able to tell you how to do that with them on the car, but I can only get a rough approximation that way.

 

[RootesRooter]

Do you have an electric fuel pump? If so, the pressure might be set too high.

If your carbs haven't been touched for a long time I suppose the washers around the adjustable jets could've dried out over the years and both went bad when the screws were turned while tuning it. Odds are pretty slim though.

Also take a close look to see if the fuel source isn't actually the plastic T-fitting between the carbs. My T split recently and at first the fuel appeared to be dripping from the bottom of each carb.

If nothing becomes apparent, I'd take it back to the British Mechanic for another look-see.

 

[RootesRich]

If your carbs haven't been touched for a long time I suppose the washers around the adjustable jets could've dried out over the years and both went bad when the screws were turned while tuning it. Odds are pretty slim though.

My bet is this is exactly what the issue is. If you go to the Stock Forum and scroll down, Kevin, aka Q on the Forum, just experience this same issue. I sent him a set of NOS O rings and he's crossed referenced them to ones that can be purchased at Napa.

 

[Hodee]

I had the same issue with gas dripping onto the exhaust. Napa has the o-rings but I was not able to get the ones that are oil/gas resistant. they still work but i will be looking for the Vitron type that can handle the gas/chemicals etc.

 

[inline_eric]

So guys since I will be replacing the O-rings does that mean my adjustments will be out of whack afterwards? Or is there a way I can change the O-rings and keep it running the way it is?

What I really need to do is learn more about these carbs...I am so used to Ford Autolites and Holleys. These are unfamiliar and therefore intimidating.

Does anyone know of a book I can buy that will explain everything on these carbs?

Thanks,
Eric

 

[RootesRacer]

By replacing the "o-ring" I assume you are talking about the main jet o-ring and not the bowl sealing gasket.

To replace the main jet o-ring, you will have to remove the main jet, which by definition means you will disturb the settings.

If you screw the jet all the way in and carfully count the flats and starting index, you will be able to return the main jet to a position very near the original jetting.
When you reinstall the main jet, screw it all the way in and then back out the counted number of flats for re-index.

You DONT want to disturb the jet centralizing nut (the larger hex fitting nearer the float bowl) as this will require you to perform a jet recentralization, which can be fun...

 

[RootesRacer]

For a book reference, many auto stores sell haynes manuals.

There is one on weber carburettors that also has information on SU and Stromberg carbs. It says this on the front.

 

[RootesRich]

You DONT want to disturb the jet centralizing nut (the larger hex fitting nearer the float bowl) as this will require you to perform a jet recentralization, which can be fun...

Unless you live in the Denver Metro area as both Jarrid and I can do this in our sleep and with one hand tied behind our backs. Ok, perhaps not the latter...

 

[RootesRacer]

Unless you live in the Denver Metro area as both Jarrid and I can do this in our sleep and with one hand tied behind our backs. Ok, perhaps not the latter...

Rich,

I dont mess with stroms anymore.
I will leave that to you...

 

[RootesRich]

Rich,
I dont mess with stroms anymore.
I will leave that to you...

Fair enough, but you COULD recentralize the jet in your sleep if you wanted to...

We got to get the Denver group together at least once before the snow starts flying. Perhaps after this weekend my schedule will free up a bit and I can organize something.

 

[inline_eric]

I think i am getting confused on what could be leaking...are we talking about the larger outer nut on the bottom of the carb because that is what I am talking about.
Thanks,
Eric

 

[RootesRacer]

I think i am getting confused on what could be leaking...are we talking about the larger outer nut on the bottom of the carb because that is what I am talking about.
Thanks,
Eric

The larger nut is the centralizer nut.
It has an o-ring too but since it does not get turned but on installation and centralization, it usually is not the source of a leak.

The actual main jet also has an o-ring but since it rotates inside the larger nut, the o-ring is more likley damaged.

If there is any doubt in your mind that both need replaced, then absolutely do so.
If you replace the larger o-ring in the centralization nut, you have ZERO chance of just putting it back together and expecting to to run well without recentralizing and retuning both carbs.

That is if this is the case, consider that you will need a FULL overhaul of the carbs (diaphragms, gaskets, needle and seat, o-rings ETC).

 

[RootesRacer]

We got to get the Denver group together at least once before the snow starts flying. Perhaps after this weekend my schedule will free up a bit and I can organize something.

Plan it out. I am more or less available on weekends though Saturdays are taken till around 1pm.

 

[inline_eric]

The larger nut is the centralizer nut.
It has an o-ring too but since it does not get turned but on installation and centralization, it usually is not the source of a leak.

The actual main jet also has an o-ring but since it rotates inside the larger nut, the o-ring is more likley damaged.

If there is any doubt in your mind that both need replaced, then absolutely do so.
If you replace the larger o-ring in the centralization nut, you have ZERO chance of just putting it back together and expecting to to run well without recentralizing and retuning both carbs.

That is if this is the case, consider that you will need a FULL overhaul of the carbs (diaphragms, gaskets, needle and seat, o-rings ETC).

I got the sunbeam going again today…just finished putting on a soft top that some guys have been helping me with in another thread…anyway I think the back carb it where my leak is…I really want to get the car out but the leak is bothering me, The PO said he rebuilt both carbs…and I have remnants of the rebuild kits he used so I know he did something…I don't really have a clue about these carbs…so if I remove the main Jet what is going to come out…gas, springs, nothing??? Does anyone have pictures of the process…

Thanks,
Eric

 

[DanR]

Eric, Go to the top of the FORUM Page, look for : "TECH DATA",

Click on it, go to the bottom of the page for the tech manuals and you can find the Section on FUEL Systems, download this and it will provide good info on your Carbs.


If you are not satisfied letme know and I'll try to get you some PIC's from some where else.

 

[DanR]

Eric, I mis read your post.... I thought you were using Strombergs..... for Zeniths there is coverage at the top of the TECH DATA page for Zenith

 

[inline_eric]

Ok guys...I have been looking into the source of my leak...there seems to be gas on the back side of my back carb...so I am thinking the gas is leaking through the float chamber gasket...The PO told me he had rebuilt both carbs and there are remnants of a rebuild kit, so I tend to believe him. I guess my question is can I replace the gasket on the float chamber without removing the carb and will this disturb my tuning....
I still can't find a good manual dedicated to these Zenith Stromberg carbs...any suggestions.
Eric

 

[RootesRacer]

Ok guys...I have been looking into the source of my leak...there seems to be gas on the back side of my back carb...so I am thinking the gas is leaking through the float chamber gasket...The PO told me he had rebuilt both carbs and there are remnants of a rebuild kit, so I tend to believe him. I guess my question is can I replace the gasket on the float chamber without removing the carb and will this disturb my tuning....
I still can't find a good manual dedicated to these Zenith Stromberg carbs...any suggestions.
Eric

To start, what exact carb model do you have?
Most of us were thinking that you have zenith stromberg CD150s (strombergs).
Others are thinking you have zenith 36WIA/WIP carbs.
They are different as night and day.

 

[inline_eric]

I have zenith stromberg CD 150...I wasn't aware I should be refering to them as strombergs...when I google "zenith stromberg cd 150" information of my carbs are all I get from my query. Sorry about the confusion...thats why I posted in factory original because these are the carbs I see on most original series 5s.
Eric