Atomic 4 1978 carburetor

[Peter Cashin]

Hi
I’m doing the idle adjustment to my Trusty Atomic 4. I removed the high speed needle plug to adjust the high speed needle. Once I did this Gasoline started to flow out. Is this normal? Am I supposed to adjust the needle while running or while stopped?
I’m doing this due to the plugs getting carbon fouled and I’m running too rich I guess.
Thanks for the help.
Peter
Catalina 30 - Sunkissed

 

[shemandr]

As I remember from my A4 on my Ranger 29 that is normal. Not to be confused with OK. If the fuel tank is above the carb, the only thing stopping gasoline from over flowing the bowl is that needle valve.
Are you ready to shut off your fuel feed every time you leave the boat. And even every time you shut the engine off.

 

[Peter Cashin]

Well I do currently shutoff my fuel tank when I leave the boat. That's not a problem. I guess I have to stop the engine each time to adjust to slow the fuel. Well hopefully it only takes 1 or 2 tries. Thanks

 

[Boatyarddog]

As I remember from my A4 on my Ranger 29 that is normal. Not to be confused with OK. If the fuel tank is above the carb, the only thing stopping gasoline from over flowing the bowl is that needle valve.
Are you ready to shut off your fuel feed every time you leave the boat. And even every time you shut the engine off.

A high speed needle valve, is Not the same as a Float level needle.
The high speed needle has an o-ring installed upon it, and can become brittle.
It should not leak fuel.

 

[Rich Stidger]

On my A4 in my 1968 Morgan 30, the fuel tank was above the engine. There was a spring-loaded valve in the fuel line located at the output of the tank. Should a leak develop, the valve would remain closed and not allow fuel to siphon from the tank.
When running, the mechanical pump would over-come the valve and suck fuel from the tank.
My understanding was that this valve was a required safety feature for tanks higher than the engine.

 

[Boatyarddog]

On my A4 in my 1968 Morgan 30, the fuel tank was above the engine. There was a spring-loaded valve in the fuel line located at the output of the tank. Should a leak develop, the valve would remain closed and not allow fuel to siphon from the tank.
When running, the mechanical pump would over-come the valve and suck fuel from the tank.
My understanding was that this valve was a required safety feature for tanks higher than the engine.

That would be a check valve, and not adjustable.
As there is a dip tube pulling fuel out of the top of the tank, a check valve was installed to keep the fuel from siphoning back into the tank, creating an air pocket in the fuel line or in case of a leaking float valve. These carburetors are a Zenith brand.

 

[Boatyarddog]

That would be a check valve, and not adjustable.
As there is a dip tube pulling fuel out of the top of the tank, a check valve was installed to keep the fuel from siphoning back into the tank, creating an air pocket in the fuel line or in case of a leaking float valve. These carburetor are a Zenith brand.