Quick fuel carb wont tune....

[DonFitzwater]

That’s what I originally thought as well and brake clean was my first try. It’s tight with no vacuum leaks. I’ve often wondered about my PCV............it sure seems to move a lot of air........could that be my vacuum leak? The pcv valve really screams at idle speeds.

 

[DavidC]

Going off memory (uh oh). Back in the day I believe drilling the blades was the fix.

 

[DonFitzwater]

Going off memory (uh oh). Back in the day I believe drilling the blades was the fix.

That’s what I keep coming back to..........just trying to eliminate all other possibilities first.

 

[DavidC]

See if any of this may help
https://www.thirdgen.org/forums/carburetors/10540-whats-point-drilling-holes.html

 

[Wayne M.]

A bad PCV will surely cause your issue. Just remove and plug the line.
Back when Ford fuel injection was new, a non Motorcraft PCV would cause all kinds of trouble like stalling, etc.

 

[DonFitzwater]

So.........let me bring this to a conclusion. This will be a roundabout answer to my problems. First thing is this carb is a smidgeon big for my lightly modified 318, that is a fact. Second, all aspects of this install were correct meaning no vacuum leaks, no assembly errors, timing is where it needs to be, etc. The SOB would idle right one day and not the next. It would have horrible lean bog and stumble randomly. I couldn’t add much fuel at all through the four corner idle circuit whatsoever without having an extremely rich running condition develop. I went through this carb 2 times and verified no problems like internal leaking or slobbering power valve. Float height is a little on the low side if anything.

As a last resort and even though the little man inside my head was screaming “Noooooooo” I reluctantly removed the carb, flipped it over and drilled one 5/64”hole in each throttle plate. I installed the carb and drove it until the engine was hot. I was finally able to adjust the corner idle screws a bit. I’ve driven the truck now for 3 days and can say it’s nearly fixed. I’m pretty sure my carb will need to have the holes opened up a bit more......maybe a few more thousandths. I’m very surprised at how much snort this thing has with only a mild cam and intake as well as the carb. It will peel the rear tires at will from a stop.

 

[DonFitzwater]

One more clue in this was how much my PCV valve was screaming loud. Now with the added throttle plate holes it’s much quieter.

 

[jhenderson]

Glad you found the problem

 

[TFucili]

A reminder of when mechanical things had mechanical fixes, and not fighting "the electron ghost".

 

[DavidC]

A reminder of when mechanical things had mechanical fixes, and not fighting "the electron ghost".

The day's of points, distributor caps,rotor,and spark plug wires. The most hi tech item was the radio.