Zenith carb explanation

[ES 1800]

Would there be anyone who would be willing to describe what the various components of the Zenith carbs do? Or is there something already posted? I have the repair manuals but I'd like to understand the principles of operation of these carbs on by 73 3.0CS.

I'm curious about the vaccum can, the diaphram setup that has a rod going into the automatic choke (and its adjustment), the thermo starting valve.

What does the electrical connection on the automatic choke do? When should it have current flowing?

Can these carbs be synchronized with a Unisyn? (I use it for SU carbs.)

My Blue Book Repair Manuasl show Solex but I have Zeniths. Are they identical? What does "INAT" mean?

Thanks.

 

[61porsche]

Zeniths; further explained

The factory issued a supplemental training manual found here: http://www.sehlin.com/cscoupe/tech/zeniths/bmw2/bmw2.html

which answers most of your questions. When the Tech Info Link above is up and running this info will presumably be a part of it as it once was.

1. When the car is on, current flows through the choke housing which contains a supplemental combined electrical/ water heater. This current also supplies the idle shutoff valve and temperature choke box on the side of some types of Zeniths. ( A rectangular box with an alumium cover which supplements the choke in cold weather by a bi metallic strip that opens a port to further enrich the mixture.

2. Uni-syn: Yes, remove the air cleaner stud. Be aware that this is acceptable, but a small amount of air is going past the secondary throttle plate and won't be picked up by the uni-syn. Under ideal conditions, placing your palm over the secondary momentarily should not upset the idle. If it does, synch'ing can not be carried out until the preload is adjusted for the secondary.( too much air coming in.)

Solex and Zenith were the dominate Euro carbs. At sometime, one bought the other out, hence the interchangability of names by some.

INAT- is just the series. Several versions of the Automatic Temperature carb were made depending upon year, emissions, and destination. There probably is another acronym for the first part- don't recall at present.

If I haven't answered all your questions, your welcome to try again. A picture of your carb would help if there's something specific as some details are different and some terms apply to several items- i.e, vacumn box which could be for the secondaries.

 

[Stevehose]

There are also a number of recent posts on rebuilding/syncing etc. of the Zeniths and a search may also answer your questions.

 

[Phemisg]

The Unisyn is easier to use if you can make an adapter that fits over the top of the carb. Years ago I used the plastic top of a Turtle Wax can which was the exact diameter of the Zenith. I cut a round hole in the top smaller than the Unisyn. I just moved the assembly between the two carbs. Don't know if Turtle Wax still comes in those tins ( Zymol for me) but that's the idea.

 

[Stevehose]

I read somewhere that a Cool-Whip tub fits, I used rubber and plastic pipe reducers from hardware store for a tight fit on my synchrometers.

The Unisyn is easier to use if you can make an adapter that fits over the top of the carb. Years ago I used the plastic top of a Turtle Wax can which was the exact diameter of the Zenith. I cut a round hole in the top smaller than the Unisyn. I just moved the assembly between the two carbs. Don't know if Turtle Wax still comes in those tins ( Zymol for me) but that's the idea.

 

[bmw art car]

The Unisyn is easier to use if you can make an adapter that fits over the top of the carb. Years ago I used the plastic top of a Turtle Wax can which was the exact diameter of the Zenith. I cut a round hole in the top smaller than the Unisyn. I just moved the assembly between the two carbs. Don't know if Turtle Wax still comes in those tins ( Zymol for me) but that's the idea.

tupper ware

 

[Phemisg]

Does the TupperWare lady know about that?