dandl1862

My son has resently purchased a 1970 cutlass and is currently restoring it.This is new territory for us and we need some info about fuel pumps. When he bought the car the fuel pump on it leaked out of the hole that is in it so he replaced it with a new one. The original one did not have a return line on it but the new one does, and we were told to just plug it,so we did but the car seemed to be getting too much gas so we rebuilt the carb(2bl) and it didn't seem to change anything. It was suggested to us that the pump with the return line might be pushing too much pressure and changing to an electric fuel pump would solve the problem but we don't know what pressure the pump should be putting out so we don't know which one to put on. Any info on this would be greatly appreciated.

Oldsguy

Seems that I remember most of the early seventies models having a return line to the fuel tank. If the car has not been modified there should be a rigid fuel line secured to the frame near the passenger side upper control arm, that rigid line then has a flexible rubber line going to the fuel pump, directly next to that rigid line there should be another, smaller gauge rigid line, this would be for the return to the fuel tank. That should verify that you need the pump with the return, and where to connect it. If not, the car may have been modifed or I may be wrong, but at least that is something to check. About the carburetor seeming to get too much fuel, what do you mean? What happens? Does the carb have fuel spilling out from it? Is the engine running rich, bogging down, does it smell like gasoline? You might have something else causing your problem not related to the fuel pump because I would think that not having that return line connected to the tank would cause such troubles. I don't think you would want to use an electric if you are restoring the car anyway. Good luck, and let us know what is happening.

dandl1862

Thanks for getting back to me on the carb problem. The car seems to have no trouble taking off from a stop, no real hesitation, but in a higher gear it seems to be a bit slow to pick up when stepping on the gas. The car always has a rich gas smell emanating from the engine while driving and sometimes when parked after a drive. Also, it starts hard after being idle for some time, over night for example, and also hard if you're making allot of short stops at various locations. The only time it really starts easily is the first time you start it after having just parked it, or if its a really hot day.
The car has 4 lines coming out of the tank, the left most line (when standing at the rear) is full of some sort of sludge and will be replaced with a new line, but we are unsure of where this line leads. There are two more coming from the center of the tank, and one on the far right. None seem to be of a smaller gauge than any of the others. Could any of these be the return line?

Oldsguy

Addressing the problems you described in order:
In a higher gear slow to pick up, you mean 3rd gear or higher rpm? If higher rpm you might have a vacumm leak causing a lean out on hard acceleration, if in higher gear, I am stumped on that one.
Rich gas smell indicates the carb is probably too rich, have you set the idle mixture screws? and has the car had a tune up (should have asked that first) it needs a tune up if you haven't done it. This will effect a lot of stuff. New points, plugs, condenser, distributor cap and rotor would be a good start, then set the timing with the vacumm advance disconnected for about 12 before TDC, reconnect vacumm advance, adjust the idle to about 1100rpm in park or about 900 in drive. Then set your dwell to about oh, say 32. This is a reflection of your initial point gap setting. Then at a good idle in park set your idle mixture screws ONE AT A TIME turning in slowly about 30 degrees and waiting while listining to idle, when the idle begins to sound like missing and chugging a little then back off that screw a little, then do the other screw. This should help a lot.
As for the four lines and identifying them, I don't remember and would have to take a look. What about the rigid lines in the engine compartment?
Hope this helps. I am just a backyard mechanic and that is a general tune-up I have done for a long time with specs off the top of my head, most are right, but the dwell might be wrong. Good luck