car was running 3 weeks ago ,but would run ruff now and then , thought it might be carb from sitting for year before I bought it , so had carb rebuilt now it won't keep running , acts like it running out of gas , so toke it back to rebuilder and it run perfect on his test engine in his shop ,put it back on and same thing happened , had it towed to repair shop and he said he thought it was in carb ,why would it run on his engine so good and not on mine , found no vacuum leaks , the gas pressure holds steady at 3 pds . anybody have any ideas what to look for ,

 

There is an old saying 90% of carb problems are ignition related. Perhaps its time to check other things.

 

Maybe gas tank has sediment and sock on pickup tube is getting blocked. You might want a little more gas pressure.

 

Missed the 3#s of fuel pressure, sorry.

 

3psi may be right for the 4GC, though - I'm not sure.

I agree, check things that were disturbed during the carb install, including fuel lines, pump, and filter.
Check fuel pump output volume as per instructions in Service Manual.
Check for disturbed wires or distributor position or components.

Sounds like the carb is fine if it works great at the shop.

- Eric

 

they told me its got plenty of spark , timing is on , hoping to get the guy that rebuilt the carb down to my mechanic whose closes at 5;30 and the guy that rebuilds the carb works at another job during day and does the carbs after work hope I can find way to get both them together and see whats up , it has 2 fuel pumps on it one on engine and an electric one , was told this car use to vapor lock so the electric was added to stop that , the guy that own and know most about the car passed away , can't get much info on car other then its been sitting for couple years , that's what made me think to get carb rebuilt , seems the more love I show it the more it fights me .

 

I agree, a clog in the fuel line somewhere restricting flow. Perhaps try this to rule in or out, take the fuel line off at the carb, have a can handy and have someone turn the motor over and see what happens, could be the fuel pump starting to "act up". Where is the fuel filter located-(don't know if this is an original 62 394 set up). Fuel sock in tank as mentioned, could be another thing, and your getting intermittent fuel flow. X2 the problem is not the carb based on what was said.

 

If you have an electric and a mechanical pump it may be that 1 of them is not working to get 3#s of pressure.

 

What about water in the fuel tank?
It's a possibility since the car was sitting for some time.
Try pouring in a bottle of fuel line de-icer that contains isopropyl alcohol.

 

... or the old porous fuel lines, in this case probably the ones between the tank and the body.

- Eric

 

just an update on the carb , it ended up being the float sticking down , the guy that rebuilt the carb came down to the shop I had my car at after half hour of all other possibility's we thought it might be he finally found it , what had us confused was 3 times we toke it off and ran it on his test engine and it would run great ,put back on my car and would not stay running , the only thing I could figure was I had 4 pounds of pressure running to the carb on my car ,his test engine has 6 pounds running to it , I think the extra 2 pounds on his engine would keep float from sticking , other then that it could have been a ghost playing with are heads , he did say when I first toke it to him the model Rochester that they put in the 62 olds can be a bit touchy , Big Red is back on the road ,