need 4barrel Holly carb inf.

Rick Mach 1 · 4 Weeks Ago

I have a 69 mach1 with a 351w. with a Holly 4 barrel. I havn't dove far enough into the car to know if the motor is original or not.The car runs, but dogs down if you excellerate unless you go slowly. Also it looks like it continues to drip fuil into the carb after it is shut off for a few minutes. There are other isues and eventionaly the whole motor will need gone through and probably rebuilt but now I would at least like to get it running well enough to move in and out of my garage. Someone told me once the Hollys were easy to work on but I don't know enough about it to start. Any sugestions

Thanks.

Boomyal · 4 Weeks Ago

How does it run at idle? If that is ok and you do not see excessive fuel down the venturiis at idle, then it sounds like the needle valves might not be shutting off or the float level is too high.

If you have no history with the carb it may be time to get a rebuild kit. Be sure to ask about the power valve anti rupture retrofit kit as well.

72 fastback · 4 Weeks Ago

Check and see if it is the front or back of carburator and try cleaning the needle and seat then re-adjust float. It might just have a little dirt in it.

The Greek · 4 Weeks Ago

There's tons of info on Holley carbs on the web. Read up on them. Once you get familiar with them, adjustment and rebuilding will be a pretty easy task. Holley's site is a good place to start reading. It's going to be hard to repair your carb if you don't know anything about it.

The problem that you're facing sounds like there's an issue with the accelerator pump, its adjustment and/or the size of the pump's discharge nozzles. The fuel leakage can be caused from a faulty needle and seat or the float levels being too high, as mentioned.

There's ID numbers located on the choke horn. The Holley site tells you how to decipher them. From all indications a complete cleaning and rebuild is in the future.

Rick Mach 1 · 4 Weeks Ago

Thanks for the info. I will check out the Holley web site. I want to learn as much as I can because I will probably have to do as much of the work on my own. I grew up in a salvage yard so I should know more than I do but it's after you grow up and move away when you realize all the learning oppertunities that suround you. My folks live over 2hrs away and is still busy working so help isn't local.
The idle is a little high and it dosn't kick down well. The dripping is from the rear section of the carb as well as the seal at the bottom feels damp so I know there is work to be done. It sounds like a rebuild kit is in order. Thanks again for the input.

The Greek · 3 Weeks Ago

Be careful with the fuel leaks. You don't want to dedicate your Mustang to the fire Gods.

mycoses · 6 Days Ago

dripping gas into the venturis after shut off sounds like a high fuel level in the bowl. Check the float level at idle which is easy to do with a holley.

Print Dad · 5 Days Ago

Hello Rick,
In addition to the great advice already given I would like to add a few more things
that I think you will be able to understand and accomplish.

I kinda go overboard at times so bear with me. I don't like to hear of gas leaks and issues.

Several things you should check:
1. - make sure the 4 bolts that hold the carb to the intake are tight.
2. - Remove the air cleaner and stand in front of the motor. looking at the carb you will have 2 sections on the front and back of the carburetor. These outer 2 sections are called bowls. Each bowl is attached with 4 screws. Make sure these screws are tight as well. There is a gasket between the bowl and the carburetor body (Actually the metering block)
3. - Look at the pass side of the carb. You will see 2 brass screws that are about 1/4 inch. These are the sight bowl screws. To examine them do this.
A. - Start car, let it run.
B. - Shut off motor and remove the front bowl screw. (Careful, gas could come out. I would put a small pan or dish under the hole. Also be aware there is a thin washer behind the screw. You want the level of the gas to be at the bottom of the sight bowl hole after the screw is removed. An easy way to tell is to gently bounce the car by pushing on the fender and releasing. You should just get a trickle of gas.

What I and many people think is that the gas is too high in the bowl. This could be caused by several things but I will not explain yet.

if you can get this far...post back with results and I will be happy to explain how to adjust the float level which controls the height of the fuel in the bowls.
It is possible that the needle and seat are sticking but I can explain that later.

I am attaching a simple pix of a typical Holley Carb...yours will look different but similar.

This should get you started.
Once you try the few things let us know what you find and we can help further.
It may come to the fact that the carb needs a rebuild but let's see what you find first. Print Dad

cindys_sn95 · 5 Days Ago

good info jim. rick, find a barnes and noble book store, get a holley rebuilding manual. jim(printdad) will keep you headed in the right direction.

Rick Mach 1 · 3 Days Ago

Thanks for all the info everyone. Print Dad, just to make sure I'm on the same page. The screw that I should remove on 3-B, is it the sight screw or is it one of the 4 bowl screws. I was picturing it to be the sight screw but wanted to be sure it says "...remove the front bowl screw..." . Just wanting to be sure. I hope I will get a chance to work on it over the next few days but we'll see. Thanks again.

Joe Bean · 3 Days Ago

Rick, here is the Holley website address that has a lot of downloadable PDF files that show everything you need to know:

Holley Performance Products Technical Library

Joe Bean · 3 Days Ago

Here's another real useful one on adjusting Holleys.

Print Dad · 2 Days Ago

Quote:

Originally Posted by Rick Mach 1

Thanks for all the info everyone. Print Dad, just to make sure I'm on the same page. The screw that I should remove on 3-B, is it the sight screw or is it one of the 4 bowl screws. I was picturing it to be the sight screw but wanted to be sure it says "...remove the front bowl screw..." . Just wanting to be sure. I hope I will get a chance to work on it over the next few days but we'll see. Thanks again.

Hello Rick Mach 1,
Sorry for the confusion. Yes you want to remove the sight bowl screw. There is a thin washer behind it. The other 4 bowl screws are just to tighten the gasket between the metering block and the bowl. The metering block is between the bowl and the main body of the carb on the front bowl, on the back bowl you probably have a metering plate (not adjustable like the front block)

As others have stated there are a lot of good places to get info on the Holley.
I was trying to have you check very basic simple things like loose gaskets etc.

Working on a Holley carb is pretty simple once you get in there but there are a lot of little passages etc.

You should be sure that the gas leak is not because of a loose gasket and then you could check out bowl heights and we'll go from there.

Post with any progress/questions

Print DAd

Rick Mach 1 · 2 Days Ago

I had some time to work on the carb this pm but I forgot to check the back bowl also. Following your directions, Print Dad, the gas started oozing out as soon as I started to loosen the sight bowl screw. I also tightened the four main carb bolts but they only took just partial turns and I didn't want to over tighten. The one spot that I found some moisture today (I'm sorry I don't know the name of it so please excuse my discription) was on the piece on the drivers side that slides along this track like section that is connected to the throtal system. It is a piece that is on the left lower/back section on that side. It was moist were it comes out of the carb. Sorry if this is to confusing. Appriciate any input. Thanks.
Also Thanks Joe Bean for those sights. I printed the info to have on record.

Print Dad · 1 Day Ago

Hello Rick Mach 1,

It is possible you have other troubles with the carb but at least we have started something.
You need to check the back bowl as well. The gas will probably ooze out of that as well. I am not sure what part you are referring to. Is this car an automatic transmission?

Well anyway there are 4 things you can try on the car to set the bowl height at the proper level.

#1 - Try to adjust the bowl height and see what it does. I will include directions to do that.

#2. - Pull the needle and seat out of the carb, spray it well with carb cleaner and then re=assemble and adjust.

#3 - - Purchase 2 needle and seat valves at a parts store or speed shop

#4. - Get a rebuild kit which will have the needle and seats.

I suggest doing things in the order I listed. Just so you know...the needle and seat is under the big screw and bolt on top of the bowl. The nut is 5/8" and the screw is made for a wide blade screwdriver. The nut does the actual adjusting while the screw prevents leaks and tightens the nut.

READ THE FOLLOWING several times before attempting

From Holley:
I think, setting the fuel level should be the first thing you do before attempting to make any further adjustments. The float level should put the fuel level just below the bottom of sight plug hole. You will make the adjustment with the vehicle on a level surface. Because you are not too experienced I would make an adjustment with the sight bowl screw in and the motor off. Make an adjustment and then let the car run for about 30 seconds. Stop the motor and remove the sight bowl screw to check. To make your adjustment you will need to loosen the lock screw on the needle and seat. This will allow you to turn the adjusting nut to raise or lower the float level. Each hex flat on the nut will change the float level approximatly 1/32". Turning the nut clockwise will lower the height of the fuel in the bowl.When you have the fuel level just below sight plug hole you will then tighten the lock screw and reinstall the sight hole plug. Make sure you have a shop towel handy in case you have any fuel leaks from the Sight plug or needle and seat adjusting nut.

You may get lucky and have a sticking needle or pehaps they just need adjusting.

It is also possible that the floats are bad but this is not too common.

I hope you can make sense of this post...if not don't try it until you post back and I will include pictures. The nut and screw you are looking for is on top of the bowl. Remove the air cleaner for easy access.

Let me know if there are ANY questions.....Print DAd

Be advised that there is a thin washer between the screw and nut and one under the nut.