Please help! Broken ZENITH parts...

[levdeb]

All fixed... thanks guys!

[ddubois]

The "needle" things are your accelerator pump nozzles. Search eBay for 'Porsche Zenith" and you will find someone who is selling some (although pricey). They commonly break taking them out. If they don't break then they are likely plugged and a pain to clean.
The "ring" thing is a backing plate for the air enrichment diaphragm. They also commonly break. You don't need the air enrichment circuit. It's a great source for vacuum leaks. If you want to understand what it does and how it works search and you will find plenty. To disconnect it get 12 3/16" vacuum plugs and stick them on the 3 ports on each diaphragm housing and the 3 ports at the base of each barrel. You will also need a 1/8" vacuum plug for the right side carb. What you are doing is removing all those vacuum hoses and pipes associated with this circuit and plugging them. You can leave the wire connected to the solenoid on the right carb if you want, or disconnect it, it doesn't matter. Also make sure the set screw on the left carb bellcrank is not making contact with the microswitch as it could potentially screw with your idle adjustment.
Then replace the diaphragm in the housing that comes with your rebuild kit, bolt the housings on the carb, and screw in the 2 large set screws (one on the housing at top center, and the other smaller screw just to the right of the diaphragm housing. Depending on how well you do at jetting your carbs and setting the air bypass and idle mixture, you may get a little backfiring at higher RPM deceleration with your foot off the gas (this is one function of this air enrichment circuit).
I've done this on my 71 911T and after countless hours jetting/adjusting the carbs it runs great with little to no backfiring (only when cold).
One last note, my rebuild kit did not include o-rings for the idle mixture screws (the ones with springs). I forget the size I bought at Parker, but go to any o-ring supply shop with the needle valve and they can help you size the o-ring. But be careful they or you do not damage the needle end.

[levdeb]

Thanks ddubois! Any reason to keep it?? Also, I understand where all the plugs will go except the 1/8 plug on right carb. Is that to plug the solenoid hole if I remove it?? Thanks!

[ddubois]

Originally Posted by levdeb

Thanks ddubois! Any reason to keep it?? Also, I understand where all the plugs will go except the 1/8 plug on right carb. Is that to plug the solenoid hole if I remove it?? Thanks!

No need to keep the circuit unless you're having backfiring problems. The 1/8" plug is for the vacuum port at the base of the right carb directly above the solenoid that goes to a 'T' that then connects to the pipes that go to each diaphragm housing. You'll be removing those vacuum pipes.

[levdeb]

Thanks! Off to Autozone in the morning to buy fuel line and vacuum plugs! Really appreciate it Doug!

Now as a film actor, I will need directions to your place so my wife and I can crash there during Sundance.... lol!

Thanks again man.

[levdeb]

All plugged Doug! So do I need the vacuum line that runs between the two carbs anymore? Should I plug it, or is it a dead line now anyway.

Thanks so much man. Can't wait to get her running!

Really appreciate your time,
Bill

[kkinzli]

Levdeb,

That Zenith looks great with all of those vacuum ports plugged up. I am currently in the process of tuning mine and will probably do the exact same thing. I see you are from Parker. I bounce between Fort Collins, Denver, and Albuquerque for my graduate research. I am originally from Denver but have only had my pcar in Albuquerque. Are there any groups you would recommend looking into when I get back at the beginning of November? Thanks for all of the posts on your Zeniths. They have been super helpful

Cheers,
Kristoph

[rw7810]

You can actually take the unit in the middle right off. You don't need it.

[levdeb]

Then you have to tap that hole (no giggles) and can never use that circuit. And then you can't have those sweet blue vacuum plugs.

[Wayne 962]

Please don't edit your original post and remove important information - it makes the thread useless for people viewing the archives.

Please replace your original post with the information that you posted.

-Wayne

[levdeb]

It was a picture of a broken nozzle I was needing. I was told to remove them to save bandwidth but you are the boss!

Everything zenith related is at:

Zenith 40 TIN Carburetor Manual