Ford Mustang Forum banner

1 - 5 of 5 Posts

·
Registered
Joined
·
2 Posts
Discussion Starter #1
Hi Guys, first time post. I've just got my first Mustang 1967 with 289. 4 Barrel Holley with Vaccum secondaries. New Fuel Pump, New Fuel filter, New Spark plugs. Timing OK. New Carby Kit. Idles normal when choke on. Dies as soon as choke off. We thought it may have been vaccum leak. Doesn't appear to be that. Adjusted floats and idle. Any ideas would be much appreciated.

I'm in Australia and pretty excited to have the car. Just can't wait to get it running enough to drive around the block!
 

·
Banned
Joined
·
612 Posts
I know it's not the solution you want to hear, but Holley carb's are junk. I've got a 2nd gen camaro that had one on it and it leaked fuel (signature Holley problem), worked great one day, the next day it would give problems. If you want a good reliable carb for a street machine switch it for an edelbrock carb.

Holleys are really only good for 2 things. All out race machine (because you have to constantly adjust and play with it), or the garbage can. An edelbrock carb will offer years of trouble free use. Set it and forget it! You will never be satisfied with a Holley, it will almost always need adjustment and they are very finicky.
 

·
Registered
Joined
·
324 Posts
Unfortunately I agree with Dynobrat about the trouble free use of Edelbrock carb versus Holley. But you have a holley on your car and there is no reason you cant use it. If it will run on choke and not at idle it means you are way to lean with choke off for some reason. Check around again first for a vac. leak, if car has power brakes make sure to check booster for leak. you didn't say whether you have had the car running before your carb kit with this carb. If it ran previously it should run now. Since you have set the float levels and I assume they are correct. Try adjusting the idle mixture screws on the carb. Good starting point is 3 turns out from fully in. Enclosed pic of a holley carb with screw circled in red. there are two of these screws one on each side.
 

Attachments

·
Registered
Joined
·
2,905 Posts
Hello Badshamrock,
The debate over carb brands is one that will likely
rage on for years and years. In my opinion it is
often what we get used to and feel most comfortable with.

NOW for the issue.

It sounds as though you are on the right track. My feeling is that either
the carb is NOT adjusted right or pehaps you have a vacuum leak

PART ONE - -setting the carb is pretty simple but remember a few things.
A GREAT starting point for a Holley idle cicuit is one and a half full turns out from a gently seat.
Turn the 2 idle mixture screws in all the way to just gently seat the screw. Then back off the screws 1 and a half turns from the gentle seat.
Now you are ready to fine adjust the carb. Start on one side of the carb and back off the screw another 1/4 turn and see how the motor sounds. Then you do the same amount on the opposite side.

The goal is to have both sides of the carb adjusted closely.

You can adjust using a vaccum gage - -a tach - or even by ear.
Which ever method you use - -you will continue to back off the screws a little
at a time untill you hear the motor rpm start to drop.
Same holds true if using a tach.

The point is - -you evenly back off the screws and you will come to a point where it starts to have a negative affect on rpm, vacuum etc.
It is at that point that you turn both sides in about one half turn.

My next thought is that you have the car set to idle on fast idle screw.
This screw is on the pass side located behind the choke housing. This screw keeps the car idling when the choke is ON only - -

When the motor is warm the idle setting is don with the screw on the driver side of the carb near the gas pedal linkage. Sorry if this sounds too simple BUt some people may not know.

Once we set up the carb - -then you should check for vacuum leaks.

A number of ways to do this.
1. - use a vacuum gage and check the readings BUT
many people don't have a vacuum gage.
So the next method is to start the motor - spray a little starter fluid around th base of the carb and the outline of the intake (outer-edge). If there is a vacuum leak - -the rpm's will pick up. CAUTION - -using the starter fluid will likely eat the paint on the intake.

This helps you if the leak is sucking in. If the leak is blowing out - -and you don't know - - take a mixture of dish detergebt and water and spray the solution all around the intake and see if you see bubbles form. This indicates a leak that is blowing out.

So in conclusion - -here is what I would do

A. - Check for hoses that have fallen off or have cracks\
B. - Make sure all porst on the carb are capped if not in use.
C. - Make sure the PVC hose is secure and attached
D. - Adjust the car idle speed screws and then
E. - Adjust the idle mixture screws.

Hope this helps

Print Dad
 

·
Registered
Joined
·
2 Posts
Discussion Starter #5
289 Idle Issues...

Hi guys, thanks for the input. Car was running very very roughly before I put the kit thru the Holley. Would start but not idle then the fuel pump threw it in, so I assumed that was the problem originally. Replaced that and here i am. Will let you know how I get on with it. Have a bit of a look again tomorrow hopefully. I appreciate the suggestions.

thx
Badshamrock
 
1 - 5 of 5 Posts
Top