So, when I bought my truck, it had the original holley on it, List 6947, on it. During the effort to get it running, I borrowed a known "good" carb to eliminate the crusty carb as a variable. That helped me narrow down to a leak from the spacer under it and bad diaphragm in the distributer. Before I put the original back on, I choose to rebuild it, and found massive corrosion/dust from the baseplate screws as I removed them out of the throttle body. I then chose to purchase a Holley 65-1850S to get it going for now. Got everything going and running decent. This was about a year ago, now for the problems. About 3 months ago, it started taking its own sweet time starting, I figured with the cold and the ethanol gas, it would be better after it warmed up here in FL. Then about a month and a half ago, I had a backfire that was heard 7 townhomes away, since then it has been very difficult to start, but will eventually start. Last night while I was reading Turbohunter's article on manifold/port vacuum, ( https://www.ford-trucks.com/forums/1...nts-issue.html ) I decided to go check where mine was drawing from, which is ported, as set on the original List 6947. I pulled the cap off of the manifold port at the baseplate and had gas dribble out of the vacuum port. Did I blow the power valve on a carb that is supposed to have a blowproof valve or is this something else?

 

What kind of setup did you perform with the carb? Everytime a carb or pump, tank, etc is replaced the float level should be reset. Sounds simple, and maybe you know this but there's no way to tell from your post if you do. It would be the first thing to check.

One thing to look at with suspected carb problems is the spark plugs, the way they look will help diagnose. Maybe post a pic of plugs?

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the Holley 65-1850S does not have externally adjustable floats, I have not pulled the carb yet or pulled the plugs either. The gas dribble kinda concerned me. When you look at this image, the outer plug under the fwd fuel bowl is where the gasoline was dripping from. I did the normal tuning of idle mixture and idle speed with vacuum gauge and tach along with setting timing with timing light to 12 deg BTDC and 700 RPM in Park at idle

 

Could it be flooding, and there's why fuel at manifold port? How old is the fuel pump, I'd start with a brand new one if springing for a new carb, that way everything is on the same sheet of music. And check fuel float level after that, and for debris in bowl or float seat.

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I put this on FE Power forums just now rockitt, but since I'm here.
If it will idle, turn your idle mixture screws all the way in. If it dies then your valve is not blown. If it still runs then you did blow it.

 

I was gonna mention that, supposedly modern carbs are immune to power valves blowing out, tho who knows. Backfiring is bad for carbs.

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Agree to the check.

Contrary to Holley's propaganda, that power valve protection ball & spring dealie will not save a power valve. I have the same model - 4160, three years old - and had a wee fart through the carb one day.....and voila! Blown power valve.

If you have to start the truck with the pedal to the floor like it's flooded - ('cause it is), you have a blown power valve.
If you smell real "rich" exhaust ( unburnt HC) at idle, you have a blown power valve.

Once you pull the carb, check the floats for proper setting - turn the bowl upside down - the float should set parallel to the bowl 'top.'

The 4160 power valve comes stock with a 6.5

 

The wife chose working in the backyard as THE PRIORITY for today, might sneak out tonight and hopefully not wake up the neighbors with a BACKFIRE , if not, I will do some work tomorrow

 

Amazing how loud those can be...

 

Went out for a few minutes, it does have a pump shot when you crank the throttle by hand. Wouldn't start, will charge battery and try some more tomorrow. First, will try with no pump of throttle, just turn engine and see what happens.

Question, if the bowl drains empty for whatever reason, the fuel for the accelerator pump comes from the chamber under the bowl, correct? If so, then the next step would be to pour a little fuel through the vent into the bowl, right?

 

I'm guessing you are going to try to start it with no pumps to see if fuel is introduced through the maybe blown valve. Ok I get that. Curious to see if that bears fruit.
About your question.
You said you are getting fuel when you give it throttle.
Which suggests the bowl is not empty.
So I'm not following you here.

 

I am assuming the shot of fuel is from the accelerator pump, not out of the bowl through the idle slots under the throttle blades or the boosters

 

The bowl supplies the accel pump through the bottom of the bowl, so there would have to be fuel in the bowl. Did I say bowl enough?
Have you had any luck starting it yet?
Just thinking about it, and all your symptoms.
It does SOUND like the p valve has blown as the chamber that supplies the p valve with manifold vacuum could be full of fuel and drained out the manifold vacuum port as you stated.
If you can't get it started to do the test I'd just rip it apart and replace. Then you know.

 

OK, ended up overheating the starter side of the solenoid at some point during my exercise in frustration. Took it off and went to get new one and realized I had forgotten to mark wires when I went to install new one. Is it red/blue on "S" and brown on "I" or vice-versa? This was around 3:30 or 4 o'clock, decided to step away from the truck for a few hours... then ask the stupid question

 

You've got it.
Red/blue S
Brown I