Hey everyone I am having a wierd problem and I hope you can help. I got my new shortblock in about the same time I bought a new 950Hp carb, so it's been a little while getting everything working right. The engine runs fine and the carb seems to run great until it's run for a while. I can drive this thing around for about five miles and it runs fine , but when it runs a little longer than that it acts like it's flooding out to the point of cutting off. I can shut the fuel pump off and it will run fine until it starts to run out of gas. I have changed the fuel pressure, adjusted the float levels and everything I can think of but nothing helps. If I didn't give a acurate enough symptons just ask. Thanks for your help. Joe

Maybe its just getting to hot... try a wood spacer
under the carb to see if that helps

Makes me think you got a coil breaking down..not enuff spark..so you think it is rich..

Thanks Mr P. I thought that also but the carb don't get that warm. It has a Super Sucker spacer on it also.

My son said the same thing about the coil. But why would it run fine as soon as I turned the fuel pump off.

whats your fuel pressure set at?
sounds to me you got a stuck needle and seat.

Thanks for all the replys. Mr P You are right I don't shut the car off I just shut the fuel pump off and it runs fine until it starts running out of gas. Then I turn the fuel pump on and it fills up the bowls and starts running like poop again. I am open to all possibilities at this point keep them comming.

Needle & seats. is the fuel pressure gauge reading ok?

Check your secondary needle & seat. If it's leaking just a little, fuel could be dripping down the secondaries causing the crappy running. Shutting the pump off causes it to level out and quit dripping.

What about a leaking/blown power valve? When it's cold it needs the extra fuel. When it's warm it's running rich and stumbling.

Bad pump umbrellas can cause fuel to exit over boosters/vents when you stomp on it , could also be fuel pullover from squirters if check valves are missing/not seated , are bowl vents clear? , have sec jets had extentions fitted along with correct floats? , stuck floats? ................just some things to check.

Have you looked down the carb when the problem is
happening, you might get some insight to the problem

what kind of gas are you running? pump gas nowadays will boil at a very low temperature. i had pump gas (ethanol free) boiling at what felt like about 120 degrees! the carb was barely warm, and the gas was boiling violently! car ran like poopy.

Ok I messed with it all day. I did get the carb to duplicate the problem in the garage. I found if I get the engine nice and hot and drop it in gear and stand on the brake to about 2200 rps it will start to shoot fuel from the front vent tube. I can rev it up and it stops and if I let it go back to a idle it will stop. This is driving me crazy. Any more ideas ?

do you have clear sight plugs? if so, see if the fuel is boiling.