Had an issue last week on a ride... in the 56 with stock Y block from probably a car...
traveled 45 miles, then stopped for an hour, then another 45 miles, then stopped for 2 hrs
then another 50 miles... no real issues each leg..did note a 'burp' one or twice on that last leg.
after about a 50 minute time, fired, i stalled it, immediately refired, idled though parking lot,
pulled out to street to travel home and it falls flat on its face in middle of street...
would of course crank and no run... "most" of the time when you hit the key this thing is running almost just needs a 'bump' of key to run....
fellow traveler stopped to assist... had spark, there was fuel in the transparent filter, and could see it pulse (stock mechanical pump) but no run...
we checked few other items and best guess was vapor lock... I had an ice pack with my drinks and
put it on/near the fuel line... and waited... after about 15m, no dice..
called for a tow... and still gave it periodic attempts over the next 90 minutes still no dice
got it home with tow and slipped it in garage and just walked away.......

today......... raised hood, noted Zero fuel in the transparent filter... sprayed some gasoline in carburetor... without foot on pedal, tried it and it fired for about 10 seconds.
went around again and dribbled additional gas in carburetor, and in the holley 2bbl 2300 vent... got back in and foot on pedal, immediately fired and stayed running..
let it idle for a few minutes got out to look under hood,
plenty of fuel in the transparent filter, but it was not completely full..and i could see it pulse
I stabbed throttle a few times under hood and it was like nothing happened...

So.. I am thinking a weak fuel pump.. (and where the hell did that fuel go in the filter over about 6 days ???) this thing has always been
hard to start after sitting a week or so...

I have NOT removed the integral canister filter on the pump, but yep, it could be an issue.. but the entire assembly is over 18 years old to my knowledge....
so why not replace the entire assembly?

O rielly has a Delphi pump with integral filter, have to order, and a 'precision' about 10bux cheaper and in stock...

What are thoughts on the current supply quality... (am specifying for like a 64 y block, or even an FE pump as i understand all will interchange.... thanks in advance...

 

Rock Auto has the Delphi on closeout:
https://www.rockauto.com/en/moreinfo...488278&pt=6256

Other options include the Carter M4008 available from many sources.

Ford interchange numbers:

C3AZ-9350-U
C3SZ-9350-F
C5SE-9350-A
C6OE-9350-C
D0TE-9350-A
D0TZ-9350-A
D2OE-9350-EA
D2SE-9350-BA
D2TE-9350-GA

 

The back flow check valve in the fuel pump might be going bad and the fuel drains backward into the tank. Also, this is why it is hard to start after sitting for a while, because fuel has to be be repumped up to the carb because the fuel line has drained backwards. Just a guess though???

 

General fuel delivery problems may be one of the following;

• Contamination of debris or water. Water will not pass thru a paper filter element.
• Contaminated fuel pump. The pump has check valve(s) that open and close and if the inlet valve has debris under the flapper it will not draw, this could be intermittent as you describe passing the debris. Or maybe something in the pump is otherwise broken.
  
• Fuel line from tank to pump inlet drawing air and not allowing a siphon. Loose fitting or pin hole in steel line.
  
• Carburetor needle and seat stuck shut. (not likely, but possible)
  

I would start with filter’s, catching the contents into clean container to inspect. If pump has paper filter you can slice the top and bottom off and spread the accordion to see exactly how dirty. If it is an early style pump with a perimeter of body screws you can lift the top half (which contains the check valve) without removal of pump. Do this by removing the in / out lines and lift the top and you will see the check valve(s) in the top portion of the pump, they are round about ½” dia. Remove and look for dirt under flapper. Make sure you don’t flip them when you put them back as they're directional. I mention flapper clean out as the rest of the pump is (including large diaphragm is pretty hardy)

Just some thoughts that may be useful. Good luck.

 

Thank you for the suggestions and the tips on diagnosis, this is not a screw assembly pump...

yes, have feeling that check valve is a bit bonkers,
I will examine the line from pump to tank closely... and do realize it could suck air and not leak...

Mainly because of the potential check valve issue, probably going to go ahead and replace the pump...

Just a bit concerned with the quality of the current available offerings.

will check out the rock auto... sometimes there's a % off code posted.
picked up a glass bowl AC filter assembly at recent swap meet... may try to plumb that in to eliminate some rubber lines, using NiCu tubing.. thinking 5/16 tube should be sufficient...

thoughts on current pump quality??
think O'R has a warranty and is 8 miles from me, rock auto may have match warranty, but of course harder to facilitate....

 

I guess you got to go with what is available and convenient. I would still try to identify how much debris my filter's caught. If you have a dirty tank you do not want to prematurely recontaminate your new pump. If you suspect a dirty tank maybe you could short cut a bit of a tank clean out if there is a drain plug in the bottom of the tank? Or possibly add a non paper inline filter before the pump inlet. My thought being a paper filter maybe a bit too restrictive on the draw side of the pump?

 

I'm a fan of the FE style with the screw on canister. I used to buy them for under $20 bucks!

 

the existing pump is of this style with the canister on the bottom... pleading ignorance, does it filter incoming or outgoing ??
as it is in the lowest point of fuel flow, "if' there's condensation accumulation can see where it would blind
when last doing my fuel gage couple years ago, tank looked clean through the hole...
will be investigating all suggestions

just to make a decision on 'which pump' and will go with the built in canister style.

 

still not 'started' on this project... but

last week took time to examine after sitting six day... the transparent filter was empty, so proof of back-flow.... but one point. on the hard to start after sitting.. this is a holley 2bbl with the side
inlet, not bottom inlet... so the bowl must or should still have fuel in it.. don't think it can also siphon out...

now back... the transparent filter was empty, took a small plastic bottle with fuel in it and sprinkled down the carburetor, and dribbled some in the vent tube...
it almost immediately fired... then a stall......... sprinkled some additional fuel and it started and i let it run for about 10 minutes... that's been about a week ago now
have not examined again...

still on the fence on the pump.. a delphi or 'whatever'... i think part number is same be it for a Y block or an FE engine...

also, on the pump with attached filter, does it filter on inlet or on the outgoing circuit... If on the inlet can see where it would protect the pump. Is a filter on the outgoing side 'really' necessary??

 

Seems likely the drain back from your upstream clear filter is a break in vacuum at the pump. If the pumps directional valve catches debris and doesn’t seal completely, that would allow for the bleed down.

Good question that I pondered with your previous post about pump filtering on the incoming or outgoing side of the pump. Logical to be on the pump inlet so not to contaminate the pump, but I don’t know that. I bet you could determine that with the pump in a bench vise if it’s coming off anyways?

I have shared your same troubles in my youth. After a few frustrating no fuel hard starts along with a stuck on the road dead fuel pump scenario. That is when I figured out how to clean out the directional valves on my re-buildable pump. Not long after that, and a second “stuck on the side of the road” I went ahead and replaced the original scaled tank. Fuel problems solved for decades that have followed.