Holley Carburetor Question - 1965 Mustang

If you remember my thread from last week I was having issues with my 1965 Mustang with a worked 351W not running smooth at a steady speed which eventually over 10-15 miles got much worse. Idle and WOT seemed fine. I determined that I have good spark and good fuel pressure to the carb so now I'm looking at the carb. I figured I would check the floats first since that should have been the easiest thing to check. Primary float was good. Secondary float was off as the fuel level was way too high and it was pouring out the sight hole so I immediately plugged it. Well, the manual didn't say to drain the bowl before trying to lower the fuel level. Apparently the adjustment doesn't work right if you don't drain the bowl. I kept turning the float adjustment nut (yes I did it in the right direction - clockwise) and nothing seemed to change because I didn't drain the bowl. So now I realized that all my turning must have tore the gasket because you know what it's not even there (or else it was never there to begin with ???).

So here are my questions.

If the screw threads directly into the valve and the screw sits directly on the nut that sits directly on the carb, how does the adjusting nut work and why does the gasket make the difference? The nut doesn't appear to have any threads and the gasket is what makes it work? Now that there is no gasket the nut just wobbles all around.

Can I completely unscrew the screw to get the gaskets back in or will I not be able to get the screw threaded back into the valve without pulling the bowl off?

The nut turns the needle/seat assembly up and down in the float bowls. The needle/seat assembly is threaded on the out side, and the housing of the float bowl has internal threads that the needle/seat assembly screws into. You can completely unscrew the lock down screw to replace those little gaskets, the needle/seat won't drop into the float bowl.

(quoted from post at 13:40:45 09/14/17) The nut turns the needle/seat assembly up and down in the float bowls. The needle/seat assembly is threaded on the out side, and the housing of the float bowl has internal threads that the needle/seat assembly screws into. You can completely unscrew the lock down screw to replace those little gaskets, the needle/seat won't drop into the float bowl.

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ok. That all makes sense. Do you know why my adjustment nut is so loose and wobbly and doesn't turn the needle/seat assembly? When looking at diagrams online I don't see how a gasket is going to change that. The nut currently has no resistance like it is adjusting anything and moves all over the place. Is there a gasket to sit inside the nut between the nut and needle/seat assembly to close the gap and create that resistance?

The nut is not threaded it has two flats so the nut will turn the needle/seat assembly in the float bowl housing.

Here is a video from Holley on how to adjust the float, they also have other videos showing how to adjust the idle speed, idle fuel mixture, and other adjustments.

Here is a link for you https://www.youtube.com/watch?v=ge-mIk6nEYQ

There is only two gaskets one below, and one above the adjustment nut (you can lift the nut off, the needle/seat won't fall into the float bowl.

best thing to do is get a good edlebrock or Rochester and hand the holly on the wall,...may be able to tell i'm not a holly fan, seems they always need adjusting.

(quoted from post at 15:02:02 09/14/17) best thing to do is get a good edlebrock or Rochester and hand the holly on the wall,...may be able to tell i'm not a holly fan, seems they always need adjusting.

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Haven't worked on a Holly in 30 years, never liked them, but seems to me that the threads in the bowl were easily stripped out. Then you had to buy a new bowl.

Worked on lots of Holleys in my youth. Loved them as there were all sorts of parts easily available to customize them for any application one had in mind. Super simple to work on and straight forward IMO.

if your nut is not adjusting anything it would mean that you have adjusted the needle assy all the way down into the fuel bowel so that its flush with the top of the boss on the bowl...if you take the top screw out and remove the nut you will see what I mean...you should be able to get a hold of the 2 flat spots on the needle assy with needle nose pliers and screw it back out in order to put the adjusting nut back on...there are 2 paper gaskets that only seal the nut and screw on top from leaking under pressure...if you cant retrieve the needle assy you will have to remove the bowl assy as a whole and get it from the inside...if you have damaged the needle valve (Viton tip) then you will have to replace just the needle assy which are available at most car parts stores or performance shops and can be done without removing the carb or the bowl..do not replace with an edelbrock...they are a poor copy of a thermoquad and most end up at swap meets or junked out...the only thing wrong with holly's are people don't know how to adjust them....theres a reason why racers still run them or variations of them ..if you have more questions shoot me an email ...hope this helps

As others said, you've screwed the needle valve down too far. You can turn it back up to where it belongs, about 1/2 the thickness of the nut.

I don't think it damaged anything, but may have bent the float.

The reason the bowl needs to be drained before adjusting, is when you turn the needle down, you are pushing the float down, displacing fuel already in the bowl, so it comes out the level hole.

Try adjusting it again, but be aware you can only raise the level. Once up too high, then turning the needle in will push the float down, giving a false reading.

If you do manage to tune the Holley to the point you are happy with it, keep your eyes and nose open for fuel leaks! They are notorious for leaking both internally (gaskets and power valve) and externally (gaskets, orings, and accelerator diaphragm). Many a fine restoration has been destroyed by Holley carbs.

ok so here's where I'm at. I got the nut back on the valve. I started about half way. Let all fuel come out sight hole. Plug sight hole. Turn adjustment nut clockwise. Start car and let run for a minute. I did this 3 different times adjusting the nut as far clockwise as possible by attempt #3 and the same exact amount of fuel came out the sight hole after each attempt to adjust. I cannot get the fuel level below the sight hole. For what is supposed to be a simple procedure, this sure isn't working for me.

Can you think of any reason why after following my procedure noted above that the fuel level has not changed at all? Could the float be stuck? Could I have bent the float that bad that I can't even get it adjusted? I know to let the sight hole open when I'm adjusting the level up, but when level is high I don't let the sight hole open any time other than checking and draining, correct? Could I be getting a false reading the way I'm doing it?

you say you are trying to adjust the secondary float..unless its a dbl pump holly the only way to get the fuel out of the bowel is to drain it as the vacuum secondaries only open and draw fuel at wide open throttle...there is a way to "trick" it but with a limited exp its not easy...and that would allow you to start from the beginning...if you have a syringe you can draw fuel from out of the hole you are talking about and try to reset the level but if you did bend the float as steve said it would still have to come apart

If the needle and seat are leaking, even when being shut by the float, it will flood. If the float has fuel in it, or is bent and hangs up on the bowl, it will flood.
Jim

the fuel in rear bowl will not drop till the secondary's open up. that will never happen at idle. only at w.o. t. once secondary's open up. in other words floor it. you will see if secondary's even work.

I have tried to reply 2 times,3rd a charm??

bad needle and seat get a Eldelbrock and never look back

Something that always worked for me.
Remove the sight plug, place a rag under the fuel bowl and shake the car sideways to slosh some of the fuel out of the bowl, a couple of good shakes will slosh enough fuel out to allow for adjusting the float level. Remove the gas soaked rag and with the needle valve adjusted down start the car, if fuel fills the bowl and runs out the sight plug the needle valve is stuck or has trash in it, at that point the needle valve will have to be removed and cleaned or replaced.
If no fuel leaks out slowly turn the nut counter clock wise to raise the needle valve until fuel is at the bottom of the sight plug hole just ready to leak out, that will have the float set at the proper height.
Holley's are great carbs and are one of the best performance carbs ever produced, I've owned several and worked on more than my share.
I like them well enough that I have 3 Holley two barrel carbs on my Ford 406 FE engine.

Holly's are junk, rottonchesters are junk, when carter sold the AFB design to elderbrock and they modified it they came up with a truly efficient carb. check ebay or CL you will see.... scarp prices

If you ran the needle all the way down and its still pouring fuel out the check hole the bowl may need to come off... I adjust them with the engine running.

https://www.youtube.com/watch?v=ge-mIk6nEYQ



https://www.youtube.com/watch?v=Ctw7Xrtytww

Google it lots of info... Good carbs in my book... Down draft carbs have a window one of the first thinks you should have done was look thru it.