1928 Buick Standard Marvel carburetor

[michealbernal]

Thanks to everyone's help I got the Marvel carburetor on my 1928 Standard rebuilt and installed.  It ran great for a while but now it has started flooding.  After I start the engine it immediately begins to run rich until after running about 20 seconds it stall out.  A that point fuel is dripping from the air intake.  I tried readjusting the float level but that did not make any difference.  The fuel level is not overflowing the float bowl.  I tried closing down the needle but that didn't seem to make any difference. Can anyone provide insight into what the issue might be?  Any insight appreciated.

[Roger Barrett]

Are you using the vacuum tank or a fuel pump? If you have a pump you need a pressure regulator to cut down to no more than 1or 2 psi. In any case, the fuel level in the bowl should be just below the top of the main discharge nozzle. Too high and it will run out the nozzle and onto the floor. We set up these carbs on the bench with whatever pressure they will be seeing and set the float so the fuel is just barely visible in the main nozzle. These carbs are not great even by standards of their day. That said, they will run acceptably if everything is right. The fit of the pot metal air valve in the main body is crucial. Also be advised that these units can have a slow leak with modern gasoline when they are in perfect shape. The castings are so porous 21st century gas will seep through them.

[michealbernal]

I am using the original vacuum tank for fuel delivery ti the carburetor.  

[Terry Wiegand]

Check that the vacuum tank is operating properly.  If it is not, you will have problems like you cannot believe.  Ask me how I know this.

 

Terry Wiegand

South Hutchinson, Kansas

[Brian_Heil]

You can take the cover off the bowl and watch things work (or not work) with the engine running.

 

With this method I have found saturated floats, floats that are cocked and rubbing on the bowl wall and hanging up and poor sealing float needle/seats.