What Carb spacer to run and Holley carb issue.

[ZZ4CutlaSS]

When it is cold how well does it start?
How long can you drive before you experience driveability problems?
What exactly does it do when it starts acting up?
Do you have a mechanical fuel pump and how about some pictures of your fuel line routing?

When its cold it starts great and it acts when sitting for more then 15 mins when hot and I go to restart acts like its flooded. And I do have a mechanical fuel pump that came with the turn key engine. And far as pics the car is dismantled finishing a restoration. Just trying to make sure I can figure out this problem once I get it back together. I did order a carb spacer but will not try it unless its still peculating.

 

[pontiacgp]

I'll ask the owner of our race cars. He's a holley guy...his only fault..

 

[online170]

I don't agree with your theory. Only time I've had this happen is with incorrect fuel bowl level. You're sure you're adjusting it as per holleys instructions?

Only other thing that comes to mind is incorrect gas cap. Vented vs non vented. Take off your cap and see if the fuel stops dribbling out.

 

[ZZ4CutlaSS]

Now that I have the engine back in I think I figured out my issue but not 100% yet. My car originally had a V-6 then I swapped in the V-8. I had to move the fuel line from the pass side to the right side and how I did this was I bent some 3/8 fuel line. And ran it next the the brake line for the pass side which runs right in front of the oil pan sump. Now that the headers are installed I noticed how close they are to that brake line and pretty sure the fuel was getting hot and when the engine was sitting I'm sure with out air flow it caused my percolation issue. Hope this theory is right but I still ordered a carb spacer.

Here is the area I was referring too!

 

[LS1GN]

I wouldn't buy another carb just yet.

You seem to have a fuel not carb problem. What exactly is the fuel pressure? I think 7.5 psi is max it will run at 4.5 or 5.

IIRC gas "boils" at a lower temperature than water - so 170 or 180 is waaaay too hot for fuel. I wonder if you could take a meat thermometer and somehow check your fuel temp after you've run it for a little while. There have been millions of carburetors on the road that successfully ran without needing a phenolic spacer.

 

[pontiacgp]

I would get the fuel line out of that area..I thought you said the line was routed in the stock position and it was away from heat sources?

 

[Tank]

Here is my theory: Your getting way too much fuel for your motor. The black smoke/hard start is highly rich overflooded motor.
First use a fuel pressure guage and find out exactly what your PSI is that your running. Find out what psi is needed for your carb. most run around 5-8 psi depending on performance. You may be running 14 psi or more depending if your running an electric fuel pump or mechanical.
Next, if above seems to be fine, make sure your idle/air mixture screws are adjusted evenly and correctly according to max engine vacuum. Holley offers great instructions on how to do this. Also, make sure your choke is set correctly.
Check accelerator pump and step down to a less powerful pump in your carb. also make sure the carb is jetted correctly for your motor.
Overall, I honestly think you have too big of a carb for your motor. I would look at ultimately going to a 600-650 cfm 4 barrel carb.
Use holley's carb selector to determine carb cfm needed.
http://www.holley.com/applications/Carb ... ection.asp
or these if you know a little more about your motor.
http://www.carburetion.com/Calc.asp
http://www.4secondsflat.com/Carb_CFM_Calculator.html

 

[ZZ4CutlaSS]

Here is my theory: Your getting way too much fuel for your motor. The black smoke/hard start is highly rich overflooded motor.
First use a fuel pressure guage and find out exactly what your PSI is that your running. Find out what psi is needed for your carb. most run around 5-8 psi depending on performance. You may be running 14 psi or more depending if your running an electric fuel pump or mechanical.
Next, if above seems to be fine, make sure your idle/air mixture screws are adjusted evenly and correctly according to max engine vacuum. Holley offers great instructions on how to do this. Also, make sure your choke is set correctly.
Check accelerator pump and step down to a less powerful pump in your carb. also make sure the carb is jetted correctly for your motor.
Overall, I honestly think you have too big of a carb for your motor. I would look at ultimately going to a 600-650 cfm 4 barrel carb.
Use holley's carb selector to determine carb cfm needed.
http://www.holley.com/applications/Carb ... ection.asp
or these if you know a little more about your motor.
http://www.carburetion.com/Calc.asp
http://www.4secondsflat.com/Carb_CFM_Calculator.html

The only reason its smoking black is because its percolating in the carb after engine is at operating temp as is left to sit for about 15 min. When I go to start it after it has been sitting is when the issue begins. It only smokes about 2 seconds and clears up immediately. I have tried a fuel pressure regulator per Holley tech line. It did not seem to help with the pressure at 5 psi. Pretty sure like others have said its probably my fuel is getting to hot and thats about the only thing I have not tried yet. I just rerouted my fuel lines and should be able to update with some pics and see how it acts up soon.

 

[ZZ4CutlaSS]

So far so good with my carb spacer. The fuel pressure gauge shows pressure when shutoff now it never did that before and starts back up when I let it sit for a bit.