Floatless Carburetors

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Tadpole
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Floatless Carburetors

Post by Tadpole » Fri Apr 07, 2023 1:40 pm

Has anyone ran a Carburetor made without a float on their T with success? Seems like something that would have caught on if they worked as well as they claimed? I ask this question with little carburetor knowledge so thank you for your patience.


speedytinc
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Re: Floatless Carburetors

Post by speedytinc » Fri Apr 07, 2023 1:46 pm

Do you know of an example that has no float? If such a thing exists, how is incoming fuel regulated?


Scott_Conger
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Re: Floatless Carburetors

Post by Scott_Conger » Fri Apr 07, 2023 2:00 pm

They are vacuum operated devices. Typically a fine needle on the end of a vacuum pot...as vacuum occurs, the higher pressure below, lifts the pot, opening the regulating needle (which is tapered to vary the mixture of fuel). Some features such as the pot/needle are similar to an SU, but are NOT the exact same thing...they just share a few principles. I'm aware of a couple versions but am not by any means a student of them.

I don't think there was one which could compete with U&J, Zenith S4BF, etc.

At best, I think they were an alternative to stock carbs (NH, L-4, etc). They were fit to lots of cars and I think their scarcity today is indicative of their popularity.
Scott Conger

Tyranny under the guise of law is still Tyranny

NH Full Flow Float Valves™
Obsolete carburetor parts manufactured

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Topic author
Tadpole
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Re: Floatless Carburetors

Post by Tadpole » Mon Apr 10, 2023 7:27 pm

Thank you Mr. Conger, your carburetor knowledge is invaluable!


Erik Johnson
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Re: Floatless Carburetors

Post by Erik Johnson » Mon Apr 10, 2023 8:21 pm

You've probably seen a floatless carburetor on a lawn mower or snow blower.

Example of a carburetor with no bowl or float on this 1959 Briggs and Stratton from a Toro reel mower. It draws fuel directly from the tank.

This style of carburetor is still in use today - refer to second photo of a new one.
Attachments
briggs & stratton.jpg
carburetor.jpg

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Craig Leach
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Re: Floatless Carburetors

Post by Craig Leach » Mon Apr 10, 2023 9:41 pm

Hi Erik,
Technicaly that carb has a bowl that is open on top and the level is controled by the bowl that will spill the excess back into the tank. The short
tube draws fuel from bowl & the long tube is attached to a pulse pump that draws fuel from the tank. Don't get me wrong I used those Carbs. In
Kart racing on Methonal years ago and they work great. I just don't want the gas tank hanging under the carberator on my T. The vacuum
controled flow is still used today in weed-eaters & leaf blowers in states they are still legal. They were used in updraft carbs on aircraft for a
long time and even on Harley-Davisons but are signifacantly more suffisticated than what was available for T's. I dought I would be able to put
up with what I would get from most T'ers if I put a side draft Tillotson on my T.
Craig.

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Craig Leach
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Re: Floatless Carburetors

Post by Craig Leach » Mon Apr 10, 2023 10:43 pm

Hi Erik,
On second thought you are correct there is no float in that carb I was thinking bowl not float sorry if I miss spoke.
Craig.

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