OK I examined this carburetor issue more closely. Before taking the carburetor apart to replace the accelerator pump, I decided to see how it was working to begin with. It seems my bowl is always empty after a few days of sitting. Not sure why exactly. Evaporating? Maybe...but the accelerator pump was a first start.

I popped off the air cleaner, shot some fuel into the fuel line with a turkey baster bulb until the float cut me off, then pressed the accelerator lever by hand. I saw and heard the obvious squirt into the carb throat. This is my original blue-rubber accelerator pump, not the leather one yet. First thing I noticed was fuel bubbling out from the bottom of the carb where it's fastened to the manifold. So I'm wondering how that leak might affect my starting. Any thoughts? (Note- I tightened the bolts and it's no longer leaking)

 

That's a vacuum leak and will cause poor cranking,idle and running.

 

I wanted to post an update to my '56 F-500 272 Y-Block starting woes. After going through the entire carburetor I was unable to get the truck to start any better. I added an electronic fuel pump so I get instant fuel. It still didn't start. OK, so I'm getting fuel and I know it is squirting into the intake. I figured it was time to take a good hard look at my electrical and ignition system. Firstly, my battery was shot. So I got one mother of a battery from NAPA that puts out over 1000 CCA. Still didn't start. But it sure cranked quickly! I decided to get a tester to measure how much voltage my standard NAPA 12V coil was putting out by connecting it to each plug boot and giving the truck a light cranking. I bought the tester on Amazon and started testing last Wednesday. I was BARELY arcing at 10,000 volts when cranking the truck. As soon as I pulled the bolt back any further I had zero arc. That's a serious issue right there and I finally felt I was onto something. I got a new coil. Still not even hitting that 10K volts.

Now for every step here below, I went back to check the voltage out of the coil. After each change the voltage from the coil never hit the 20,000 volts to give me a strong, solid blue SNAP that I needed to start the truck (NAPA said the two coils I now have from them should be giving that 20K)... Read on...

1) Replaced the positive battery cable, lightly sanded all contacts, applied dielectric grease and bolted it down. Still not even 10K volts out of the coil.
2) Replaced the negative battery cable, sanded, greased, bolted. No change.
3) Replaced the ignition wire from the ignition post of the starter relay to coil +, sanded greased, bolted. Nothing.
4) Replaced all of the spark plug and ignition cables, distributor cap and, Hell while I'm in here I'll just change the plugs (not that the plugs would change the coil voltage...) Nothing.
5) Checked my points. A little high...maybe .19. Adjusted to .015. Good. Also nice and gray. Not burned. No change.
6) Replaced the condenser and put in new points, adjusted to .15. No change.
...At this point I'm running out of things to check...but I kept going.
7) Replaced the small ground wire grounding the distributor inside. Nothing.
8) Here I noticed that the wire connecting the distributor to the Coil - terminal was frayed and old and realized I never changed it out when I had the engine out. That cable was at least 30 years old; was hard, dry, rotted and caked in crud and even had some exposed copper where the cable cracked. So I replaced it with a nice 16 gauge cable with soldered copper ends (as all of my new wires are) and sanded the bolts on the coil and the distributor housing, greased and bolted it down, prayed and cranked it. Twenty. Thousand. Volts. Of. Heavenly. Blue. Snapping. Energy.
9) I made sure everything was back together and hopped in. I took a deep breath, and the truck started instantly. I couldn't even believe it.
10) Since I had been cranking the truck during the testing, and since the truck always seemed to start after cranking it on and off for a minute (just before my battery said, "That's it I'm done.) and pumping the snot out of the gas pedal I thought maybe it won't start again if I let it sit for a few days. I went out this morning and tried it again. It fired instantly again. It seems to run a heck of a lot better too.

Amazing how a short piece of thin wire can make an entire truck, and the driver's life, miserable...and yet so happy when it has been replaced. I am going to frame the old wire and hang it on my wall!

 

Well why didn't you change that wire first?


Great write up on your troubleshooting and resolution. I'm sure this will help other folk down the line.
Makes me want to go out and double check my wires.
It can be the smallest things that cause us the most grief.

 

Ha! If I only I started at the ignition/distributor end and not the battery end, right?! But then I may have been lazy and not added new, clean and properly secured wires/cables throughout the entire ignition! If your truck requires 100 pumps on the accelerator pedal and several minutes of cranking yes, you might want to go look at that @#$%&#& distributor-to-coil-negative wire! (Insert crazy angry face) hahaha

 

"Ninety per cent of all Carburetor problems are Ignition related". Whoever came up with that was really on to something.

My favorite "new" toy the last couple years is the Oscilloscope. Ignition analyzers display both primary and secondary ignition waveforms for each cylinder, in either raster (stacked) or superimposed form. They are worth their weight in gold for troubleshooting. Keep your eye peeled at yard sales and such, I found one online for $40. They will show faults like that in 30 seconds. It's better using these than throwing parts at a problem. Ask me how I know!