Holley carb whistling................UPDATE 11-12** FIXED

[Charger4404spd]

Some of you all remember when I said my new Holley 750 was whistling just off idle. Chryco said it was the secondary butterflies. He was correct. SO I just took it off and returned it for another one, same shit still!

I am now almost bald. Yep, pulled all my damn hair out. At at a loss as to what to do. I do know this carb is going back and I am getting my money back.
ANy advice is more than welcome.

Been thinkin about a Demon! Maybe.   Any comments?

[Runner]

     my 750 dp on my roadrunner never whistled until i swaped in a holley hp mainbody and now i have get a little whistle right as i crack the throttle.

   i dont think a demon will be the answer for you.  have you tried calling holleys tech?

[MTPOCKET]

Do you have a spacer block between you Carib and manifold? What type of manifold do you have stock or performance? I had a spacer on my Holly crab and it would whistle replace with a different space and fix problem.

[cudaken]

 Been 20 years sense I had that problem. One time it was a blowen power valve which should not happen now and other was a clooged vent tube which is rare.

I going to guess you have a vacuum leak. Are you using the vacuum port that is on the base plate under the front bowl? Easy to miss, I have done it onces.

                        Cuda Ken

[Charger4404spd]

Yeah I am using a spacer. I was using a phenolic 1/2", but the air cleaner was hitting the hood, so I am using the aluminum plates/gaskets.
It is a stock manifold and yes I did plug the vacuum port on the plate. Havent talked to Holley tech yet, but I guess that will be in the very near future.

[Just 6T9 CHGR]

A freind had the same thing.....turned out it was worn bushings on the throttle shaft

[Ghoste]

But it shouldn't happen on two new ones in a row.

[Chryco Psycho]

so adjust the opening of the secondaries , open or close them slightly to get the whistle to stop , there is a adjuster screww under the passenger side of the base plate or just bend the tab slightly

[Charger4404spd]

I did adjust the secondary screw on the other one. With the plates all the way closed, I could see a small amount of light thru one edge of the butterflies. This other new carb is the same way.
Is holley slacking on their quality or is this normal?

I will open the plates a litttle on this one and see what happens. Will this effect anything?

[Headrope]

Are your gaskets "ported" to match the manifold, spacer and carb?
I experienced a similar mystery whistle after putting on an aluminum spacer. In my case the spacer was also an adapter plate that mated a square bore carb to a spread bore manifold, so was shaped different on each side. I used square bore gaskets on both sides (between manifold and spacer, and spacer and carb. The square gasket portruded into the airflow on the spreadbore side of the spacer - kinda a square peg in a round hole situation. Like blowing over a blade of grass, air flowing over the gasket made a whistle.

[Charger4404spd]

Headrope, I use square bore open gaskets. It is actually 4 gaskets with 3 aluminum gaskets used to help control heat from the carb. I have to use these or a spacer so the Holley linkage on the baseplate will clear the intake.

[Chryco Psycho]

opening the rear plates will increase idle spee which can be adjusted back down by closing  the front plates slightly
I don`t think this is a quality problem at all , more just a coincidence of the amout of vacuum you are making & the set up of the carb you are using creating a whistle

[Charger4404spd]

OK, just tried opening the secondary plates. Problem is, I had to open them approx. a quarter of an inch to get the whistling to stop. As I did this, I turned the idle screw down to get back to my idle speed and the idle was very choppy at best. Really sounded like crap.
Sinse this carb is new out of the box, I went ahead and checked the float levels and the accel. pump adjustment. Ok there but I think I need to replace the pump cam with a higher profile. It has a dead spot when reving quickly. I also adjusted the idle mixture screws. Only had to turn them out 1/2 turn each to get the highest vacuum reading, which is 12".

Timing is 12 at idle and 35 total.
I also emailed Holley about the whistle to see if they had any clue as to what to do. Not going to hold my breath waiting on a response though.

[MTPOCKET]

Are you using the 4 hole spacer? See pic.

[Charger4404spd]

Nope this here.

[Ghoste]

What intake?  I'd look at a four hole spacer if it were me, even if it was a small one.

[Charger4404spd]

Stock intake. I only used this one because it was lying around and I can alter the thickness so the air cleaner doesnt hit the hood.

[MTPOCKET]

No change to 4 hole spacer thats the problem. The spacer you are using is causing your problem.

[Charger4404spd]

OK, I will pick one up tomorrow and give it a try.

[Just 6T9 CHGR]

I am running NO spacer and my Holley doesnt whistle......

Very odd problem  Hope you get it fixed

Keep us updated!

[Charger4404spd]

Chris, I am using the spacer for 2 reasons. 1- So the linkage on the baseplate wont hit the intake, and 2- To keep the carb from vapor locking on the hot summer days.

[cudaken]

 Just buy a 1/4 single pices gasket. I all so think the spacer you are using is the problem.

                                   Cuda Ken

[Charger4404spd]

My local speed shop was out of the 4 hole spacers, I will have it on by the end of the week and will give an update then.

KEN: I have to use a small spacer so the holley linkage will clear the stock manifold. I cant use anything over 1/2" because then the air cleaner hits the hood.

If this 4 hole thing doesnt work, OFF with the Holley and I am going to try an Edlebrock AVS or AFB.

[cudaken]

 I think I posted 1/4 gasket. As far as the thottle cable, use a washer under it to raise it, if it to low see if you can use a spacer under the stock one to rasie it a little.

I just look at your last posting again. Use a washer under the hook up. I was running a stock 72 440 with a 750 Holley, onlt problem I had was the kick down clearing the M/T valve cover. A PIC would help and I will see if I can dig some up as well.

                             Cuda Ken

[Charger4404spd]

Thanks guys for the input, you all fixed her.

I installed a 4 hole spacer and all is well. No whistle at all. Im excited, I never dreamt that would have been the problem.
Thanks again!


Steve