Zenith 40 TIN Carburetor Run Test.

Zenith 40 TIN inspect and repair decel system.
This Zenith carburetor set was built by another shop a while ago. The carburetors did not run right and were hard to tune with backfiring. The deceleration system is often the culprit. Rather than removing the system from your zenith 40-tin carburetors, just get it to work how it was intended.
As you decel, say, down a hill, and there is a high engine vacuum with less fuel, the decel system provides air and fuel to prevent backfiring on deceleration.

[@keithgarland3404]

Another useful video, I'm an old tech, and I am learning from your work, never too old to learn, thank you for sharing your knowledge, you know your stuff 👍

[@klassikats]

Your
Welcome Keith,
I find that I learn more now than I did when I was in my twenties and thirties. Maybe its a better understanding of the big picture and how things work together..
Kurt

[@jeromelangenderfer8853]

Great content. Enjoy watching a master at work.

[@klassikats]

Glad you enjoy it!
Kurt

[@frankmoron5787]

effin awesome vid, learned a bunch, thnx u guys. and i was wondering about the jetting w tst engine prob being a different displacemnt, since the weber rebuild vid, but u answered that too.

[@klassikats]

jetting will always be unique to the engine that the carbs are being run on, the location, and the quality of the fuel being used. Running on our test engine does not confirm jetting. It does however confirm operation and adjustability of the carburetors.
Kurt

[@RichieRich845]

👍

[@klassikats]

Thanks
Kurt

[@vwfanatic2390]

I acquired a ‘70 911t 2.2L with Zenith 40TIN’s but was supposedly running properly without the “deceleration circuit”.
Do I need to get and install that if I don’t have smog requirements to worry about? Will it harm the engine or carburetors to run without the “deceleration circuit” ?

[@klassikats]

As long as the system has been completely disabled then it wont hurt the engine. The system was designed to slow the engine deceleration so that it does not stall and to also burn off excessive fuel in system due high manifold vacuum in the carburetors.

[@vwfanatic2390]

@@klassikats Thank you. Yes they have been fully disassembled, thoroughly cleaned, and meticulously restored, with close attention paid at all the points you make in your rebuild video. Thank you very much for that as well.