Fuel Regulator Setting

[Bill Lee/Virginia]

I have two 1932 B-2 carburetors on my Speedster and am using a Fuel Pump and Fuel Regulator with the Fuel Tank located at the rear of the car.

I can tell no difference between Fuel Regulator settings of 1, 1-1/2, 2 or 2-1/2 PSI.

What PSI do you recommend I set the Fuel Regulator?.

Many thanks for your info and advice.

Bill Lee/Virginia Peninsula

[Jim/GA]

Is the fuel filter before or after the pressure regulator?

If after, you want to compensate for the filter eventually getting plugged up and go 2.5 psi.

If the filter is before the pump, then it doesn't really matter. Pick any number from the above that you like.

[john in illinois]

You always want the filter before the pump. Protects pump. Regulator after pump.

I do not know what pressure for Zenith carbs.Since they are normally gravity feed I woukd guess 1 1/2-2.
John

[Fullraceflathead]

Gravity feed is about equal to 1 lb pressure from what I have read.

[Jim/GA]

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Originally Posted by Fullraceflathead

Gravity feed is about equal to 1 lb pressure from what I have read.

You are correct. It actually depends on how full the gas tank is.

The density of gasoline is 0.32 psi/foot of vertical elevation.

So measure the vertical distance from the fuel level in your tank down to the inlet of the carburetor... probably not even 3 feet on a full tank. 3 feet works out to just under 1 psi at the carb float valve.

This is why some people have a fuel flow problem when they add a paper filter to the sediment bowl of their car on the firewall (because they have a rust problem in the gas tank). It only has 1 psi pushing through it (unlike a mechanical fuel pump that can be several psi). As soon as that filter gets plugged up with fine rust and stuff from out of the tank, gravity feed does not have enough pressure to give you enough fuel to run well.

The OP says he's running Model B carbs. The stock Model B carburetor was designed to be used with a mechanical fuel pump, so it can tolerate higher pressure than a stock Model A carb (unless you removed the spring in the fuel bowl that was put there to compensate for having a mechanical fuel pump).