A14 Carb flooding

[TakemuraShuu]

Hello, I have a 1976 B210 with a new but stock mechanical pump that's having a serious carb flooding issue. I can never get it to idle for longer than 10 seconds. I would disconnect the fuel line and crank with throttle fully engaged and it would run after a few seconds for a good while.

 

I've tried 3 different brand new carbs: Weber 38/38, Weber 32/36, and now a 36/38 is mounted. I've connected a New cj7 fuel filter with return to the tank, no difference. Tried a Spectre fuel pressure regulator with the lowest pressure setting, and the pump still seems to be pumping at the exactly the same rate.

 

Very unsure of where to go from here, I'll be purchasing a fuel pressure gauge to find out exactly how it's pumping soon. Thank you.

[Dguy210]

I would suggest replacing the fuel pump then. Or going with an electrical fuel pump. Both are much cheaper options then swapping carbs. Moreover, for normal driving you would want a 32/36 for the Weber. 

[datzenmike]

Second that. I wouldn't go larger than  a 32/36 either.

 

How you know it's flooding???? If it floods, you will see gas dripping down into the barrels. Take a look. Flooding can also be from an incorrectly set float level and dirt preventing the float needle closing

 

Always look at the last thing you changed if a problem pops up. Maybe the fuel pressure regulator in the 'new but stock' mechanical pump is faulty or maybe this pump isn't for an A series engine.

 

Webers are known to not like fuel pressures over 3 PSI. New they should be ok. If you had 3 carbs on there that all flooded that would tend to indicate something else. They can't all have the same problem.

[TakemuraShuu]

25 minutes ago, Dguy210 said:

I would suggest replacing the fuel pump then. Or going with an electrical fuel pump. Both are much cheaper options then swapping carbs. Moreover, for normal driving you would want a 32/36 for the Weber. 

 

22 minutes ago, datzenmike said:

Second that. I wouldn't go larger than  a 32/36 either.

 

How you know it's flooding???? If it floods, you will see gas dripping down into the barrels. Take a look. Flooding can also be from an incorrectly set float level and dirt preventing the float needle closing

 

Always look at the last thing you changed if a problem pops up. Maybe the fuel pressure regulator in the 'new but stock' mechanical pump is faulty or maybe this pump isn't for an A series engine.

 

Webers are known to not like fuel pressures over 3 PSI. New they should be ok. If you had 3 carbs on there that all flooded that would tend to indicate something else. They can't all have the same problem.

Thanks alot for the reply folks, I'm gonna get a new pump and see if it works out better than the other. Should I get another mechanical or go electric?

[datzenmike]

1 hour ago, datzenmike said:

 

 

How you know it's flooding???? If it floods, you will see gas dripping down into the barrels. Take a look. Flooding can also be from an incorrectly set float level and dirt preventing the float needle closing

 

 

 

Simple to check, just look.

 

Where's the old pump and what was wrong with it???

[loffdaddy]

Make sure the anti dieseling valve is working. Should be at the 7 o'clock position on the carb facing you. It is electrical.

[datzenmike]

.. and how would the idle cut or anti dieseling solenoid be related to carburetor flooding?

[loffdaddy]

It will not open preventing engine from running i believe.

That's been my experience.

Don't hurt to check

[banzai510(hainz)]

All those weber have anti selionoid idle jets????

flooding is is needle valve not closing or float sinking cause has a hole in it. Which unlikely will happen to 3 carbs.

 

the mechanical pump should go limp once the carb if full if (don't have a return line)  Pull it out and try it.

 

 

 

[datzenmike]

The mechanical pump has a relief valve. When the pressure reaches the designed amount, the valve pushes open and fuel is redirected back to the inlet and is recirculated and pressure can't rise any higher. On L20B engines there is a return line to the tank but it has a restriction in it like a pin hole. Without the restriction the fuel would take the easiest path and pump right back into the tank. With the restriction pressure will build normally to around 3 1/2 PSI. The return line allow gas that is heated by the under hood temperatures to slowly be sent bask to the tank and cooler fuel circulated past the carburetor. In the event of 'vapor lock' where gas boils in the line after shut down the bubbles will be pushed out into the tank during restart. Also the fuel line pressure dissipates shortly after shut down with the return line. Given time all the gas in the tank is recirculated and all has to go through the fuel filter... not a bad thing as the tank stays cleaner.

 

End of the return line to tank.

[TakemuraShuu]

This is my first time hearing of the anti-dieseling solenoid. I bought a factory a14 mechanical fuel pump and installed (incase the other was for a different vehicle) and same situation with the flooding. 

 

The 200sx is running decent now except up hills and over 80ish mph. The b210 with the A14 is still having this flooding issue.

 

- Carb can't be the issue since I've tried 3 different Webers.

- I got the tank completely cleaned so that's not it

- it has jeep cj7 fuel filter with a return so I don't understand how it can still flood

- with bowl empty, if I connect the fuel line to the carb and crank it'll run for maybe 5 seconds then floods out

 

Might be time for an engine swap 😭

 

[datzenmike]

Re 200sx. Up hills and high speeds..... put a new fuel filter in it. They are cheap so no biggie if doesn't work. Sounds like starving for fuel. Or using fuel faster than it can get through a plugged filter.

 

Re: flooding.  Floods out.... like you can actually see gas running down the inside of the carburetor??? The fuel bowl is full to over flowing???

 

Webers are sensitive to fuel pressures above 2 1/2 PSI. Connect a fuel pressure gauge and see what that pump is putting out before you run out and get a fuel pressure regulator.

 

 

[banzai510(hainz)]

anti dieseling selinoid. Most weber don't have them but on later Model Datsun the stock carb has these to prevent run on after you shut the car off.

the selinoid will not fit the manual carb or water chiked carbs as the idle jet holder size if defferent

Edited January 20, 2021 by banzai510(hainz)

[TakemuraShuu]

14 hours ago, datzenmike said:

Re 200sx. Up hills and high speeds..... put a new fuel filter in it. They are cheap so no biggie if doesn't work. Sounds like starving for fuel. Or using fuel faster than it can get through a plugged filter.

 

Re: flooding.  Floods out.... like you can actually see gas running down the inside of the carburetor??? The fuel bowl is full to over flowing???

 

Webers are sensitive to fuel pressures above 2 1/2 PSI. Connect a fuel pressure gauge and see what that pump is putting out before you run out and get a fuel pressure regulator.

 

 

Thanks for both suggestions! I'll get a fuel pressure gauge immediately, and should've thought of a fuel filter earlier honestly 😭

[datzenmike]

You may be able to rent or borrow a gauge.