1936 Dictator 3A Stromberg carb

[1953 GMC Hydra-Matic]

Can someone please help me figure out why gas leaks from the float bowl down into the manifold. the carb was rebuilt with a new pump piston.  I took it apart and recleaned it but this morning it is still leaking from the float bowl down into manifold.

Thanks for any and all help.

Dennis

[Spinneyhill]

If is it a BXO-26, the top is very thin and warps over time. Look at the edges between the screws - they are probably wavey. The warp is caused by tight screws on a compressible gasket.

 

You may be able to bend it back to flat. GENTLY! You need a piece of flat steel, some clamps and copious boiling water. Lightly clamp the wavey top to the steel. Pour boiling water over it and tighten the clamps a little while still hot. More boiling water, more tightening. Let sit until cool and check. Repeat until flat. You may need  shims under the screw holes to get it full flat. The die cast metal is very brittle with a low melting point so be very gentle with it.

 

Also, is the float level right and does the inlet needle valve work reliably?

[carbking]

Check this link:

 

http://www.thecarburetorshop.com/Troubleshooting.htm#Fuelleak

 

If the curb idle screw (throttle positioner screw) is screwed in such that the throttle is cracked open, then the fuel will go into the manifold rather than exiting by the throttle shaft.

 

Jon.

[1953 GMC Hydra-Matic]

Stromberg carb, model ex-23.

Hello again, I have rechecked the float level and purchased a gauge to check the pressure of the fuel pump. It read between 2 and 2.5 pounds. I checked the idle screw and the needle and seat, also.  I read in my "shop manual for 1936 models" that the economizer valve may need to be taken out and lapping using fuller earth and liquid soap. I can still get it to fire then it floods out.  I have to take off the vacuum advance line from the manifold and drain out the gas.  I can't seam to find what is causing this problem.  Anyone else have any ideas?

Thanks, Dennis

Edited August 5, 2018 by 1953 GMC Hydra-Matic (see edit history)

[carbking]

A more complete description might help.

 

Will the engine not start?

 

Is the carburetor leaking after you shut it off?

 

If so much fuel is draining into the intake manifold to prevent starting, there are several possibilities, but the most likely would be a defective discharge valve under the accelerator pump allowing fuel to syphon through the accelerator pump circuit.

 

If the spring in the valve is weak, or the plunger is stuck then no amount of fuller earth and liquid soap is going to help; it will need to be replaced.

 

Jon.

[1953 GMC Hydra-Matic]

Good Morning, If I get it to start it only runs for 10 to 15 seconds at the most or it just fires and then floods out.  So it is hard to tell if the carb is leaking.I have had the valve out and the plunger wasn't stuck. If it is the valve how can I find another one. I appreciate your help/comments, I am not the world best mechanic.  I am a chef/teacher by trade and working/restoring the 36 is my hobby.

Thanks,

Dennis

[Spinneyhill]

You say it floods while running? Have you checked the float needle valve, where the fuel comes into the carb?

 

Mine would do that when there was a speck of dirt under the needle, stopping it closing.

[rbk]

Put a good fuel filter in.

Send your carburatorto Dave Thibeault.

978 897-3158.

He is an expert on these.

Gary Ash also knows these well.

 

[1953 GMC Hydra-Matic]

Thanks for the help. I talked to Dave and he has sent me a new carb kit.  I am going to change the needle and seat, hopefully this week. Hope that that is the problem. if not I am going to send it to Dave.

Thanks!