Technical 1964 Cadillac carb issue

Just rebuilt the Rochester carb on a 64 Cadillac.

It ran fine before but hesitated a bit

Now that I rebuilt it, it will idle for a few seconds and then die.

If i rev it up it's the same case.

I did not adjust the floats, I left them the same seeing as it was running fine.

 

Has the automatic choke been adjusted correctly?

Procedure that SHOULD happen if everything correct.

(1) Pump footfeed maybe 4 times
(2) Press footfeed to floor, and REMOVE FOOT!
(3) With foot OFF the footfeed (get out of the car if you wish), start engine
(4) Engine should immediately rev to about 1800 RPM and idle at this RPM.
(5) Depending on wear on the fast idle cam, it may stay at this RPM, or you may have to "kick" the footfeed for the idle RPM to drop after 30 seconds or so.

Starting the engine with your foot on the footfeed defeats the purpose of the fast idle cam.

Jon.

 

Is it starting on accelerator pump shot, or are you providing fuel to start it. If you are providing fuel and it starts/and runs then dies I'd be looking down the carb for accelerator pump shot.No pump shot I'd be suspicious that the float bowl isnt filling.A stuck float maybe.Try this use a rubber line between the fuel pump and carb.Pinch it shut with vice grips start,run,rev the motor till it dies.Now release your vice grips while tapping on the carb body near the needle and seat.That will sometimes unstick them.It also works to flush dirt out of a leaking needle and seat.Use your head think this through.Any engine needs air/fuel in the proper ratio,compression and spark.We know in your instance your air/fuel ratio is wrong.Why? Choke stuck closed or not pulling off? no fuel in bowl?Giant vacuum leak?

 

You compared all the new parts with the ones you took out, right ?
As always, your factory Cad shop manual will help you figure it out ...

 

Take it apart again, recheck that all the holes are clear, that the accelerator pump is free, re-adjust everything again according to the shop manual, especially the floats, make sure your filters are clean, try again. I’ve always had to do this 2 or 3 times to get it right. (I’m not a smart man, tho’.)


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