Zenith TIN 40 jet in bowl

[Einar Irgens]

Hi.

The pic shows the internals of one Zenith TIN.

At the bottom of the float bowl there is at tiny jet (1). I think it's supposed to feed the auxillary system (which I have removed) with fuel when you suddenly lift the throttle at high revs.



Further up there is an air jet (2) which i think is connected to (1). On the outside there is some sort of bolt (3) that I think is part of the same circuit. Can anyone confirm this theory?

Is there a simple way to blind this (sub)system completely off? Previously, I have sealed (2), but I want to be absolutely sure that no air/fuel circulates.

Einar

[Hi_Fi_Guy]

That photo is a bit tough to see.

If you do a search you find the thread that explains tapping the pipes where the enrichment hoses connect and then using a cap screw with some locktite to seal them up.

That would address part of your goal.

[911 SLANT]

#2 is Idle air correction jet

[911 SLANT]

[Einar Irgens]

No, no. These are #2 and #3.



Sorry about the bad picture.

[Einar Irgens]

I have one additional question. How do these come off? And how can the emulsion tubes stuck inside them be knocked or pulled out?

[1QuickS]

1, 2 & 3 are for delivering fuel to the emission-era "barnacle" that is attached to the side of the Zenith. #2 provides air to emulsify the fuel that is drawn through #1 and the #3 screw controls the rate of emulsified fuel delivery. The "barnacle" was activated during compression braking (throttles closed during deceleration) and a solenoid switch mounted to the flange at cylinder #6 that determined that the throttles were closed. Tighten screw #3 to de-activate this system from delivering fuel during deceleration. The idea was to add fuel during deceleration which was a lean operation (no fuel and lots of air) and lean running results in high nitrous pollution.

The brass bits in post #6 are the pressed-in brass tubes that house the emulsion tubes. Un-screw the main air correction jets at the top of these pressed-in tubes and the emulsion tubes will come out. Sometimes these pressed-in brass tubes will rotate when trying to remove the main air correction jets, hold them with pliers while un-screwing the air jets.

[Einar Irgens]

Thanks a lot, Paul. I have been wondering what the point of the system is. Does the Weber IDS have a similar system, in order to avoid backfire when closing the butterflies at very high revs? I guess I don't have to do anything, since I have already made sure no vacuum is applied to the system.

Regarding the brass pipes: I have taken off the air correction jets, but for some reason the emulsion tubes stay inside them no matter how much I shake the carbs. There is quite a lot of muck and carbon deposits inside the carburetors, every bolt and jet is sticking. Broke one of the main jets while unscrewing it.

[1QuickS]

IDS Webers have a high speed enrichment device that provides a richer fuel delivery under high RPM operation, completely different from emission era Zeniths.