Air cleaner set-up for 289-4v

[67_289xr7]

I’m not sure exactly what to do here. The car runs great, until I quickly stab the throttle. When I do that it has a split second hesitation, then takes off. It had a motorcraft 4300, that I replaced with a new holley street warrior.

I’ve had the aftermarket air cleaner on since the rebuild and wondering if an original will be better. If someone wants to critique what I’ve got, I’ll gladly take notes.

I will respect your advice, too, as I’d like this car to be better.
Here’s a few pictures. One of them is when I got it.

[SoCal_Cougar]

If its only when you try to stab the throttle or first open to WOT, I’d look into adjusting the accelerator pump on that holley, either a larger nozzle, or if it’s close enough perhaps just a different cam on the lever.

They have multiple cams here that change how aggressive the accelerator pump will deliver the extra fuel.
https://www.holley.com/products/fuel_systems/carburetor_components/accelerator_pumps_nozzles_and_booster_parts/accelerator_pump_parts/parts/20-12

Its also possible that the lever is out of adjustment, in which case you just get two 3/8" wrenches and adjust the nut and bolt with the red spring inbetween until it is contacting the lever. If it’s out of adjustment, you could be delivering the fuel too late, or keeping the lever depressed at idle and not allowing the diaphragm to fill with enough fuel.

[Redxr7]

Confirm that you are dealing with 6.5 power valve…if so then adjust accelpump to specs and go from there…you can lengthen or shorten pump shot with cam change or reposition…sometimes you need to change the nozzle size but stick with what you got until you exhaust cam changes….of course make sure your ignition and timing are properly set….and your idle vacuum reading is in line.

[Redxr7]

One more thing….the #7 and #8 plug wire cross….which could result in a misfire ….I always go 5-7-6-8 in the loom holder on the vc… btw…nicely detailed engine bay….

[Royce]

Generally this sort of problem - bog on throttle application - is caused by incorrect ignition timing adjustment. Anything that is done to the carburetor will not affect it.

Basic tune up technique is needed to fix the problem. Advance curve in the distributor, initial timing, centrifugal advance operation and adjustment, vacuum advance are all subjects that you need to become familiar with and then explore to see what they are on this car.

[67_289xr7]

Thank you for your replies. Very much appreciate the knowledge you share!

Royce, I couldn’t agree with you more and I will do that. I wrote down the areas suggested to be familiar with.

Redxr7, thanks for the wire tip. I changed it and now 6&7 cross.? The specs in carburetor manual say 65 for the power valve.

SoCal, I did what you suggested last night and first light I was out to test it and got it perfect now. Thank you, well written (all of you), easy to understand. Nice video, too helped tremendously.
The nut was close to the top of bolt. I ran it down a ways(to loosen pressure maybe?). Too far and it acted up, so back and forth a bit until I found that perfect spot. As you said, right when the bolt makes contact to the arm.
It’s a c-4 automatic, at 25mph WOT-it takes 1st gear, no hesitation at all, same at 45 mph, it jumps into 2nd.

Some history if you care to read:
I traded a customer I work with a few hours to help me install the carburetor and the first start. He noticed the spacer I had from the previous carb was too short. It ran ok, had a little hesitation just driving easy. He timed it without a timing light, said he only did that by ear.

So I made an appointment out of state, with a Mustang mechanic, 50+ years experience and still always busy:). He and his son rebuilt my transmission and rear-end.
He had it a couple weeks, told me that was cool, so long as my cougar behaved and didn’t bite any of his horses.

So, when he first opened the hood before I left, he noticed the spacer being wrong. Then noticed my ood ball valve cover(unfortunate story there). He said 67’ 289 had a 1 year valve cover. He got it running great. It was being broke in, therefore he was easy on it.
Again, I’m grateful for the help this time! Thanks

[67_289xr7]

Two books I found so far are:

1. HPBooks-how to rebuild SBF-by Tom Monroe (1978)
2. Haynes techbook-Ford engine overhaul manual (1991).
   The Haynes book page 255 talks a little about changing carburetors and the association with the air cleaner, so I think I’ll be alright with what is there, currently. I acquired the factory correct air cleaner, snorkel, heat tube and choke tube, just in case.

Also makes mention to not cross spark plug wires 7 & 8, accelerator pump adjustment;) etc. There’s not much on timing that I’ve found, yet.

As some of you know, finding people to work on these cars is hard now. I’m finding out real fast that if I want to own/drive one, better start learnin’, because taking it apart and putting in back together is a little different than getting it and keeping it running tip top.

[67_289xr7]

This was not anything to do with the carburetor. I was wrong and the problem never really went away, until now that is.

It was the timing, as noted above-thank you.
It started with a points resistance test, which showed bad. I replaced them and set the gap. Did a dwell test and adjusted the gap, again until it read around 29 degrees. Then used the timing light, which showed my timing was off a couple degrees.
The manuals to the tools are imperative.

[Royce]

Those are nice tools. You need good ones to do a good job. You did.

[67_289xr7]

Thank you for that! These were my father in laws and he felt the same as you about tools.