Zenith S4BF Carburetor

[BarnesvilleT]

I was wondering if anyone has any kind of instructions or directions to dismantle, clean and test
the S4BF. I have cleaned the outside and inside the float but was wondering what I would run into
if I started to take it apart and clean the inside. Also, is there a way to test it after to see if fuel is
getting through it.

[Scott_Conger]

Assuming the pot metal venturi is intact (which is a bit of a longshot), then separating the top casting from the lower casting may well lead to damage to it. I would not suggest separating them for that reason (plus there is little to be gained in cleaning even if you do). The only reason there would be a benefit to that is if there was no intake screen for the idle circuit. If it's there, then you're good.

If you hook up fuel to it, it WILL fill. I say that because there is every reason to believe that right now the float valve tip has a ring worn in it and the seat is similarly worn. If it runs, it runs. If it sits, it will likely overfill and drip.

They were made to specifically be a FORD accessory carb and as such, SHOULD be jetted for a "T". Unfortunately, Model T's now exist in a myriad of configurations be it cams, high compression heads, etc., and you may find that it is not jetted correctly.

As for adjusting, the jets determine the high speed richness and the little downward pointing knob is the idle adjustment: unscrew it and it leans out, screw it in and it enriches it.

BTW, nearly every S4BF that comes along lacks the correct fuel hook-up. That fitting on the carb takes a 5/16 flare (5/16 copper pipe about 5" long with a Model T specific fuel fitting on the end).

[John bevardos]

Hi Scott,
are you still making the fuel line?

thank you , John

[BarnesvilleT]

Scott, Thanks for the info. It was on a stock 1922 engine that was in a '26 Coupe when I bought it.
I am trying to get the '22 engine going with this carb so I am hoping it will still work. I will put fuel into it
and see if it holds or leaks. If I actuate the throttle should fuel come out of the jet at the bottom of the venturi?
Bill

[Scott_Conger]

If I actuate the throttle should fuel come out of the jet at the bottom of the venturi?

no

you've been around too many modern carbs! HAHA! Modern carbs have an accelerator pump to "shoot" a blast of fuel into the throttle body when stomping on the gas. This carb has no such feature, nor did any other carbs of this period

while the S4BF is a GREAT accessory carb and adds real pep to any T, your best bet on getting your T going will be with a rebuilt Holley NH carb. Dead simple and 100% adjustable for richness. You might have a great car and a pooped out Zenith and you're never going to get the car running right and will not know if it is engine or carb related. Once your new car is running happily, then swap for the S4BF and see if there isn't a vast improvement in performance (there should be), else you have carb problems

make sense?

[BarnesvilleT]

Makes complete sense. Thank you again. The excitement of buying a 100 year old car soon
becomes the reality that all you bought was a template. I guess I will have to also buy a new
intake manifold to replace the Zenith one.

[Scott_Conger]

You're welcome

used manifolds of your vintage are cheap and plentiful...Good NH's are reasonably priced, too. Pay the price for a rebuilt one from the get-go and now you are certain that any trouble you have will be something else and not the carb. Of course, as I mentioned earlier, once you're up and cruising and have mastered driving the thing, you're free to try the Zenith because NOW you know how the car should run and the Zenith should provide for some more badly needed ZIP to it.

now, the next post will be for help handling the bag of snakes that the intake/exhaust manifolds become when replacing gaskets! It's easy when you know how...just let the forum know when you're ready to do it.

[BarnesvilleT]

Thank You. It won't be long!

[Scott_Conger]

John

I haven't made any for about a year and I think I'm out of stock...I'll check

I'm out of stock but may make some this summer

[John bevardos]

Thank you Scott........bring on summer!!

John