If I press down more than 1/4 throttle engine stumbles and shuts off

I think this is it... I'll have to check mine to verify the pressure range, but it seems right. Initial setting was the 6psi,I mentioned before. (Either way it looks and connects the same.)

https://shop.advanceautoparts.com/p/holley-fuel-pressure-regulator-12-803/17120441-P?searchTerm=Holley+fuel+regulator

Good deal, just finished reinstalling the regulator with Teflon at the fittings. Wasn't sure it'd hold up to the fuel

No, I haven't got the 3 port filter or return line installed. Had some issues removing the fuel tank to install the new return.
He'll eventually have the factory setup again.

Took a little 15 second video of the stumble. Going to try to figure out what it takes to upload to YouTube. Once I do, I'll post a link to it for ya.

Let's see if this works.

https://youtu.be/rGrExHFPP8g

I'll get one this evening. Kinda doubt my neighbors want to hear me racking the pipes at 7:00 am. Lol

That seems so obvious that I'm wondering why I haven't already done it! Hahaha
Thanks bud

Good call on the carburetor cleaner while accelerating, Steve W.
I have 2 videos. 1 with slow acceleration to stumble the other I think I accelerated a little too quickly, but it does include carburetor cleaner with an improvement. I'm hoping you're able to see the butterflies in both videos.

Let me know if you can't and need a better view or anything.

CJ MEDEVAC

Regulator is directional (in through bottom abd an outlet either side)

Fuel pressure is at 6psi and my gauge was leaking fuel a little. (Very little) Carburetor had the same reaction with 10psi unregulated.

Have not had a chance to double check bowl level. However, I believe I had them set correctly

Mix screws are each out 1.25 turns from seated

Jets are the stock 57s (I thought about testing with smaller, maybe the 52s you're running?)

I bought the jeep with this carburetor thinking it was going to be a simple mixture screw adjustment issue and ended up here when it wasn't

Steve W

From what I've heard from Holley. The vacuum secondaries will only engage under a load and will not be visible "in the driveway" (No, I haven't seen fuel in the secondaries.)
From what I've noticed this stumble is preventing the engine from pulling enough load to open the secondaries while going down the road. I'm now thinking I need to try the "paperclip test" to see if the secondaries are opening.

Both of y'all
Can you see my frustration? Lol
I will happily retest anything I've tried and any/all new tests y'all have. I want him on the road!
Thanks again

No squirter on the secondary side (single pumper not double) there are jets. The jets are stock on both sides at 57.

This carb wants 7psi at idle (optimal per Holley specs) I'm 1psi low right now
I think it wants 4.5psi to run & can't remember off hand how many gpms it wants

Edit: I'll try to get a pic of my regulator and filter setup in the morning (still only have the 2 port filter installed.)

I've manually opened the secondaries as it stumbled and, yes, it picked up and ran/sounded great.

I was just sitting here wondering; if my jets are too big and my vacuum is a lot higher than Holley expected. Could my vacuum be sucking all the fuel outta the primary bowl?

Here's why I'm thinking that; stock power valve is 2.5. Makes me think Holley built it for about 6 in hg. Whereas I have nearly 20 at idle (full manifold vacuum) I've tried the 10.5pv but still had the 57 jets.

It seems to me that I should be running a smaller jets (maybe the 52) with something like a 10.5 or 11.5 power valve.

Am I way off track or does any of this seem logical?

Edit: forgot to answer your fuel question. It is ethanol gas, less than a week old. Been started everyday up to operating temp too

I've got a vacuum spring set. I'll install the lightest and change to the 10.5 pv tonight.
It'll have to be after dinner with my daughter thi, so a bit later than usual. (Probably around 730-8 Central time)
Cross your fingers for me!