Bowl leaking?

I believe the bowl is dry on my 72 gs 350 quadrajet. Starts hard after long cranking now after my rebuild of the engine. Accelerator pump works a bit better if I pour gas down the vent tube. I tried to check fuel level down the vent tube with a long toothpick and didn't see anything on it even after priming. I'll check accelerator pump again after sitting for a day. I have replaced the mechanical fuel pump during rebuild that seemed to help a bit. I believe I read 72 carb plugs didn't leak as badly as earlier ones? I haven't pulled carb off yet.

 

72 and later Rochester 4MV Q-Jets had metal plugs which were pretty solid, but if your Q-Jet is a remanufactured unit...all bets are off. Some of them still have the lousy little brass cups from earlier models which always leak, and you need to put marine-tex or some other sealant on the plugs.

 

Not been rebuilt in the 40 years I've owned it.

 

Remove the carb abs seal it up with marine Tex as stated above

 

Larry is correct! That carb needs a rebuild , epoxy the plugs , then if bowl is still empty after it sits put window less needle and seat in .

 

Yes it should definitely have a rebuild but I would like to drive it the rest of the season and try to eliminate the detonation also.

 

Accelerator pump works great after sitting a day. I found a kink in my new fuel line. Why doesn't hard line point towards the fuel pump so flexible line can go straighter?
I'm about ready to add a 90* barb elbow!

 

I'll try to go to my hydraulic hose dealer tomorrow to get a length of kink resistant.

 

I hoping this might be part of my troubles.

 

Just sitting for a week , even without the plugs dripping , Gas will evaporate from the fuel bowl . But as Larry has said its long due for a rebuild .

I experience evaporating fuel on some of my cars that sometimes sit for weeks if not months at times but don't mind the extended cranking to get fuel to the bowl because there is a better chance of building a bit of oil pressure thus lubing the bearings a bit .

 

I'm thinking the kink may have caused vacuum and sucked it dry?
It never used to be a problem and isn't getting over 180* much.
I'm having trouble finding kink resistant fuel line.

 

Maybe just try a slightly longer piece of standard fuel line. I don't have a picture, but I have not had that problem with the standard fuel line I bought from O'Reilly's.

 

evaporation and drain back are the most likely culprits.

you can switch to a non windowed fuel inlet seat if you havent already. That effectively raises the minimum fuel bowl level in the case of drain back thru the needle and seat.

You could put a check valve in the fuel filter that would limit drain back as well. basically it closes when there is no fuel pressure coming in, so no fuel can make its way back to the tank from the carb.

common common complaint.

 

Bowl still dry today. I installed the checkvalved fuel filter now. I'll check if it starts easily next week.

 

Easy to just pull it off the manifold and check the plugs. If mine sits for three days it wants a short shot of accelerant to light off so I go through one or two cans of starting fluid every year since I drive it about once every other week. Modern fuel is not formulated to stay liquid in an open container (like the carburetor) for very long (my garage has been about 100 degrees most of this week). Fuel injection is a totally closed system.

 

I really don't see any way the factory fuel line setup could kink? That seems impossible. Maybe photos of yours?

 

I just add fuel down the vent tube to fill the bowl. Then it starts right up and keeps running. Should be interesting if this check valve makes a big difference.

 

Here is the photo of my fuel line again