Dan thanks for your offer to have the corvette mechanic see this post, I look forward to hearing his thoughts.

______________
Tommy

It is entirely possible that the float in the carb has swollen up, and is sticking to the sides of the bowl. The float is made of a resin type material, and they will soak up fuel and expand. New or not, it can happen. You've done so much to the fuel system, that the carb is really the only other thing that could cause a fuel starving issue.
The check valve in the filter can be removed, but I doubt it is the problem...its only purpose is to keep fuel from draining back out of the carb.
Adding the second spacer/insulator under the carb might help, I s'pose, if it is heat related. The Q-jet should have a thick gasket under it. You might want to check and see if your heat riser(on the pass side exhaust) is working properly. If it is stuck closed, it can certainly push more heat thru the bottom of the intake, and thus transfering the heat to the carb...


______________

Joel Adams
C3VR Lifetime Member #56    
My Link


(click for Texas-sized view!)             NCRS

"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"

  I like the heat riser idea..

______________

My first parade at Carlisle 2010

Well installed second thick spacer today and she ran okay, a couple of short road runs. Then when got back in the garage and shut it down.........antifreeze started out from under engine...but found clamp lose on line from radiatior neck to overflow jug so tigthen it up and hopefully fixed that.

______________
Tommy

The heat riser I was referring to is in the exhaust, right where the head pipe bolts up to the manifold. On your '81, the heat riser will be vacuum operated, so you should see a small metal tube going down to the riser valve itself. There will only be the one on the pass side exhaust.

 I think what you are describing that you checked is the valves on the bottom of the air cleaner wings/inlets? While those being stuck OPEN would also contribute to excess heat to the carb, I can't see them causing your problem.  

______________

Joel Adams
C3VR Lifetime Member #56    
My Link


(click for Texas-sized view!)             NCRS

"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"

I have showed the information to my mechanic.  The first words out of his mouth were "It sounds like a Fuel Pump Problem".  Send me a PM and I can send you a rather large file on the Quadra-puke Carb !!  It will tell you all you nmeed to know about the Q-Jet.  I agree with Joel.  I cannot see any heat riser problems entering into this problem.  And you say that you just had the carb rebuilt?????  Whats r/s???  Oh, Duh!!  Thats the Heat Riser!!  Hope you :get her going"  Wish I was near you, I love to trouble shot problems like this!!

______________
          



(click to see a larger image)

I AGREE TAKE GAS CAP OFF

Any word on this one yet..I am curious to hear what you find.
Rich

______________

My first parade at Carlisle 2010

  Well it happened again this past Monday after a 40 mile run, came back in, stopped the engine for about 3 minutes and when restarted as I got the vette into the garage she died and I had no fuel thru the carb. We took all lines apart, checked all we could and it appears that the fuel pump is bad and this one was put on back in April. An Advance Auto one, not the higher dollar Holley pump. Anyway we never did get fuel back up from the pump so the vette is currently at the local Chevy dealer and as soon as they check it out and let me know we'll address the problem but again I am betting on a bad fuel pump.........I hope that is all it is.

______________
Tommy

Here is another REMOTE answer. The rubber fuel line from the frame area has to take a sharp angle to attach to the fuel pump on my 72'. I DID have a simular problem. The hose was bent to sharp and collapsed the line/kinked it so fuel would only flow slowly. If you replaced the pump and changed the angle of the line, it could be just a kink.  I put a metal elbow on mine and solved the problem.   Mark

______________

Click on image for full view

  Just to update all on this issue, the vette has been at Corvette Etc in Charlotte for the last week and they have been going over the entire system and most main parts such as fuel pump checked out, the TPS and choke had to be adjusted but the mechanic feels the main reason for my problem of fuel stoppage was the "S" hose from the steel fuel line running the frame from the tank that connects to the fuel pump. This hose was soft, not hard as an original hose should be. Since engine was cranking and we could not make it loss fuel again this was what was changed out and now testing the vette on the road. So far all working as should.

   I was not aware of this hose being so special and that a standard rubber hose was not proper for this operaton so hope this is the fix and if any of you have similar problems may want to check your "S" hose as well.

______________
Tommy