Fuel delivery problems, NEED HELP!!

[ramathorn2112]

I have a 1970 4dr dart with a 225. the carb is a holley 1920 and the car is equiped with the CAP clean air package. no egr, just the two valves in the air cleaner. anyways, the car ran fine when I first bought it 3 months ago. then over a period of a month, it started to run rough, like its not getting enough fuel. i changed the fuel filter n there was some sediment in it. i assume theres still probably sediment in the tank although the recent fuel filter appears to be clean. the other day it was cutting out so bad i couldnt accelerate, so i put it in nuetral n revved the engine. the first couple pumps i saw a lil black smoke in the exhaust, but the third pump produced a backfire and a big puff of blacksmoke. after the backfire it ran fine the rest of the day. it ran fine for 3 days n now its starting to get progressivly worse again. under accelleration it feels like im runnin outta gas, sputtering n what not. i pulled the plugs n they are all dry and tan in color.(thought it mite be runnin rich) theres a butterfly valve between the intake n exhaust manifolds, which seemed to be sticking. i sprayed some penetrating oil on the shaft and its not stickin anymore. im thinking the carb mite need a rebuild but im confused as to why it wil run fine some times n rough others. anyone have any advice as to what i can try?

 

[Bulldozer]

you need to rebuild the carb. the float needle and seat has probably seen better days. they are very simple to take apart , clean , and re assemble with a new kit

 

[player1up]

x2, and you'll get to clean out all of the fine rust that's sitting in the bottom of your float bowl and passages while you have it apart.

 

[moe7404]

a rusty steel line from the pump to the tank, can get a small hole in it and run ok part of the time , but fail part of the time.. check the entire length of the steel line. i had it happen on 1965 cyrysler 300. it was rusty in the frame. yes the steel line is inside the frame holding water on it.

 

[abody]

could also be a rubber fuel line at the tank sucking together

 

[68dodge]

if you are still runnig the stock fuel line over the front of the motor, you may want to move it or wrap with some heat wrap. Had problems with my sons car, after a while with the fuel line vapor locking. He moved the fuel line, worked ok.

 

['74 Sport]

There is a filter sock on the intake line of your fuel sending unit inside the tank. If you had crud in the fuel filter earlier, you might also have crud inside the tank clogging up the sock.