77 C10 350 OEM carburetor question

[philo_beddoe]

https://nationalcarburetors.com/

[Steppin Razor]

That leak may be the rear float bowl leaking. May want to see if you can snug up those bolts a little but not too tight. It doesn't take much to strip the threads in the body.

It may also be leaking a little because the fuel pump is pushing fuel past the needle. Did you get a chance to figure a way to hook up the pressure gage on the 3/8" line?

Extra fuel pressure may be causing the vacuum drop at idle.

Not yet.  Got my vacuum reading.  It was around 18"/hg for a few minutes, then dropped to 15, wavering between 15 and 16.

It looks like the booster for the AC/heater is patched with duct tape.  I did lose heat/ac a little while ago, I figured it was the blower motor.


What do I do if the fuel pressure is too high?  Tester can hook in at the fuel filter?  I'll replace that (which is pretty full) after.

Thanks and merry Xmas/Happy Holidays

[TexasRed]

The AC/heater booster? Is that the black ball thing? Or are you talking about the vacuum line that has duct tape? You could cap the port or plug the line.

Are you reading vacuum when it's warmed up?

If the fuel pressure is too high, you can either find a fuel pump that puts out less pressure or easier to do is to put a regulator to lower the pressure to the carburetor. I usually use a tee that connects into the fuel line to check fuel pressure. Just be careful. You don't need to read it for long, and it will jump a little if you tee in because the needle will be opening at idle, but you should get a good number.