Need help with Holley 750

Chip THELEGEND Johnson · 09-16-2007, 08:46 PM

I have a 4779 Holley on my crate motor stocker.
It worked fine at Darlington and Piedmont. This weekend it developed a hesitation leaving the line. Does'nt hurt E.T. Just reaction time.

I would like to send it off or just buy another carb.
Any suggestions.
Thanks
Chip

Tim Harris · 09-16-2007, 09:35 PM

Call Billy Plage.He has mine working fine.1.32 60ft

Tim B · 09-16-2007, 10:37 PM

Put bigger squirter's in it.

1347 · 09-16-2007, 10:55 PM

clean out the idle bleeds, they are probably dirty

Mike Hedger · 09-16-2007, 11:33 PM

Before you do anything major check if both accl pumps are working. If one is dead pull the squirter and see if the check valve under the squirter is stuck. Take a small pick and move it around to get it unstuck. Be careful not to let it go in the intake it is not magnetic. If it is stuck the accl pump will be very hard to depress with your finger. If it was working/ running OK and now it is not this is most likley your problem. Is it running OK other than the stumble? Hope this helps, Mike

greg fulk · 09-16-2007, 11:34 PM

Chip easy fix squiter...see what size it has& go up a couple sizes. One other thing..dose it have jet extensions in the secondary? oh almost forgot Cheap fix (or atleast try) rubber hose from the front bowel to the back....it may be dumping fuel from the front into it the carb on take off . make sure to cut a couple small holes in it for air. good luck

Ron Middleton · 09-16-2007, 11:58 PM

Chip,
1. Check idle air bleeds for obstruction
2. Check accelerator pump adjustment and function
3. check pump discharge for obstruction
4. check timing, if timing is still same then go up 1 size on squirter and see if it clears up. If weather is close to prior runs and this did not happen then I suspect timing is off or trash in circuit somewhere. If DA is different then it could be a lean condition and squirter size change should help.

Myron Piatek · 09-17-2007, 12:14 AM

All good advice. But I also believe the air was better this weekend, especially on Sunday.
If your squirters were borderline lean, the air could have leaned them out more. (footbraking)
If you're 2-stepping, it could be borderline lean jetting.

Chris1529 · 09-17-2007, 07:05 AM

The idle air bleeds won't cause it to hesitate, it would just sound like a V-6 at idle if they are dirty.
I'd say to go up on the squirters.

Is that the Texas two step you are talking about Myron? If Chip is a little lean doing that, maybe someone should have took him a couple beers! No wonder it took till 300 am to finish that race Saturday!

Chip THELEGEND Johnson · 09-17-2007, 07:47 AM

I'm footbraking between 2000 & 2500 rpm's depending on track.
The air saturday was similar to the first 2 tracks.

It is a brand new carb.
Sunday Morning:
We went up on the squirter.
Went up on the timing.
Raised the floats
Adjusted the pump arms.

It did fine the first 3 passes. 3rd rd I dropped rpm to 2200 and it did it again.

HELP ME HELP ME HELP ME.
Chip

09-16-2007, 08:46 PM	#1
Chip THELEGEND Johnson Member Join Date: Jun 2007 Posts: 284 Likes: 223 Liked 281 Times in 79 Posts	Need help with Holley 750 I have a 4779 Holley on my crate motor stocker. It worked fine at Darlington and Piedmont. This weekend it developed a hesitation leaving the line. Does'nt hurt E.T. Just reaction time. I would like to send it off or just buy another carb. Any suggestions. Thanks Chip

09-16-2007, 09:35 PM	#2
Tim Harris Junior Member Join Date: Oct 2002 Location: oxford alabama Posts: 22 Likes: 0 Liked 0 Times in 0 Posts	Re: Need help with Holley 750 Call Billy Plage.He has mine working fine.1.32 60ft Last edited by Tim Harris; 09-16-2007 at 09:52 PM. Reason: mistaken

09-16-2007, 10:37 PM	#3
Tim B Junior Member Join Date: Jun 2007 Posts: 76 Likes: 3 Liked 0 Times in 0 Posts	Re: Need help with Holley 750 Put bigger squirter's in it. __________________ Tim Blount S/C Q/R 310T

09-16-2007, 10:55 PM	#4
1347 Senior Member Join Date: Aug 2007 Location: Monroe Twp NJ Posts: 503 Likes: 1,032 Liked 992 Times in 274 Posts	Re: Need help with Holley 750 clean out the idle bleeds, they are probably dirty

09-16-2007, 11:33 PM	#5
Mike Hedger Junior Member Join Date: Jul 2007 Location: Kemah TX Posts: 93 Likes: 0 Liked 1 Time in 1 Post	Re: Need help with Holley 750 Before you do anything major check if both accl pumps are working. If one is dead pull the squirter and see if the check valve under the squirter is stuck. Take a small pick and move it around to get it unstuck. Be careful not to let it go in the intake it is not magnetic. If it is stuck the accl pump will be very hard to depress with your finger. If it was working/ running OK and now it is not this is most likley your problem. Is it running OK other than the stumble? Hope this helps, Mike __________________ Mike Hedger S/C 4646 MPH Racing and Fabrication

09-16-2007, 11:34 PM	#6
greg fulk VIP Member Join Date: Jan 2003 Location: jackson Posts: 1,165 Likes: 0 Liked 5 Times in 3 Posts	Re: Need help with Holley 750 Chip easy fix squiter...see what size it has& go up a couple sizes. One other thing..dose it have jet extensions in the secondary? oh almost forgot Cheap fix (or atleast try) rubber hose from the front bowel to the back....it may be dumping fuel from the front into it the carb on take off . make sure to cut a couple small holes in it for air. good luck __________________ Greg Fulk 308 308X P/SA "ALL AMERICAN"

09-16-2007, 11:58 PM	#7
Ron Middleton Member Join Date: Jan 1970 Location: Jackson, Ms. Posts: 350 Likes: 183 Liked 12 Times in 4 Posts	Re: Need help with Holley 750 Chip, 1. Check idle air bleeds for obstruction 2. Check accelerator pump adjustment and function 3. check pump discharge for obstruction 4. check timing, if timing is still same then go up 1 size on squirter and see if it clears up. If weather is close to prior runs and this did not happen then I suspect timing is off or trash in circuit somewhere. If DA is different then it could be a lean condition and squirter size change should help.

09-17-2007, 12:14 AM	#8
Myron Piatek VIP Member Join Date: Nov 2001 Location: Florida Posts: 1,542 Likes: 34 Liked 138 Times in 51 Posts	Re: Need help with Holley 750 All good advice. But I also believe the air was better this weekend, especially on Sunday. If your squirters were borderline lean, the air could have leaned them out more. (footbraking) If you're 2-stepping, it could be borderline lean jetting. __________________ LOCOMOTION Racing

09-17-2007, 07:05 AM	#9
Chris1529 VIP Member Join Date: Dec 2006 Location: West Virginia Posts: 1,366 Likes: 6 Liked 70 Times in 29 Posts	Re: Need help with Holley 750 The idle air bleeds won't cause it to hesitate, it would just sound like a V-6 at idle if they are dirty. I'd say to go up on the squirters. Is that the Texas two step you are talking about Myron? If Chip is a little lean doing that, maybe someone should have took him a couple beers! No wonder it took till 300 am to finish that race Saturday! __________________ Chris Bowman The Mountain State Mustang 1984 Mustang GT350

09-17-2007, 07:47 AM	#10
Chip THELEGEND Johnson Member Join Date: Jun 2007 Posts: 284 Likes: 223 Liked 281 Times in 79 Posts	Re: Need help with Holley 750 I'm footbraking between 2000 & 2500 rpm's depending on track. The air saturday was similar to the first 2 tracks. It is a brand new carb. Sunday Morning: We went up on the squirter. Went up on the timing. Raised the floats Adjusted the pump arms. It did fine the first 3 passes. 3rd rd I dropped rpm to 2200 and it did it again. HELP ME HELP ME HELP ME. Chip