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#1
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Holley Secondary Idle Screws Unresponsive
Yes, still chasing burning eyes and fuel smell from exhaust.
Primary screws work, adjusted the "windows" on primary and secondary transfer slot with carb off the car. Here is a pic of my secondary metering block, does anyone see something that might be either restricting the idle circuit or where fuel might be pouring into the carb at idle from another circuit? Thank you |
#2
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And....Happy Fourth of July!!!!!!
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#3
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PV plug gasket?
Needle and seat assembly ORings … or condition of fuel bowl where they seal? |
#4
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Look for marks on the throttle body of the carb where any of the 6 corners of the PV plug might be hitting which would effect metering block gasket sealing.
This does happen at times and if so grind on the plug.
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I do stuff for reasons. |
#5
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Secondary float level correct? If everything is correct, and you can bottom out the mixture screws without leaning, it is not uncommon to have to restrict the idle circuit.
ETA: Or very carefully open the idle air bleeds. You'll need the ability (proper drill set) to do .001" increments for this method. And the knowledge to know and recognize the effects.
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'65 Tempest 467 3650# 11.30@120.31 Last edited by Scott65; 07-03-2022 at 01:00 PM. Reason: Addition |
#6
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Quote:
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68 GTO,3860# Stock Original 400/M-20 Muncie,3.55’s 13.86 @ 100 Old combo: 462 10.75 CR,,SD 330CFM Round Port E's,Old Faithful cam,Jim Hand Continental,3.42's. 1968 Pontiac GTO : 11.114 @ 120.130 MPH New combo: 517 MR-1,10.8 CR,SD 350CFM E's,QFT 950/Northwind,246/252 HR,9.5” 4000 stall,3.42's 636HP/654TQ 1.452 10.603 @ 125.09 http://www.dragtimes.com/Pontiac-GTO...lip-31594.html |
#7
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+1 Make sure the PV gasket is seated also
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68 GTO,3860# Stock Original 400/M-20 Muncie,3.55’s 13.86 @ 100 Old combo: 462 10.75 CR,,SD 330CFM Round Port E's,Old Faithful cam,Jim Hand Continental,3.42's. 1968 Pontiac GTO : 11.114 @ 120.130 MPH New combo: 517 MR-1,10.8 CR,SD 350CFM E's,QFT 950/Northwind,246/252 HR,9.5” 4000 stall,3.42's 636HP/654TQ 1.452 10.603 @ 125.09 http://www.dragtimes.com/Pontiac-GTO...lip-31594.html |
#8
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Quote:
Tom V.
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"Engineers do stuff for reasons" Tom Vaught Despite small distractions, there are those who will go Forward, Learning, Sharing Knowledge, Doing what they can to help others move forward. |
#9
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Next time you feel like it take the base plate off the carb and post up a picture showing the throttle blades (minus main body gasket) so I can see if the 4 corner idle circuits are even there.
Tom V.
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"Engineers do stuff for reasons" Tom Vaught Despite small distractions, there are those who will go Forward, Learning, Sharing Knowledge, Doing what they can to help others move forward. |
#10
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also a lean mixture will not burn clean and give the impression of rich with stank exhaust
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#11
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X2
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Carburetor building & modification services Servicing the Pontiac community over 25 years |
#12
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Base Plate pics
Thanks Tom, here they are:
ATTACH]593977[/ATTACH] Attachment 593978 Attachment 593979 Attachment 593981 |
#13
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Secondaries
I tightened the secondary adjuster screw under the base plate and backed it off 1/4 turn, now there should be no transfer slot showing on the secondaries, is that ok? I thought we needed .40 window showing.
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#14
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Quote:
If you need to change the idle speed you can make minor adjustments using the secondaries up to a point and leave the primary plates alone. But if the secondary transfer slots get exposed at idle it can cause all kinds of off idle/part throttle drive ability issues.
__________________
68 GTO,3860# Stock Original 400/M-20 Muncie,3.55’s 13.86 @ 100 Old combo: 462 10.75 CR,,SD 330CFM Round Port E's,Old Faithful cam,Jim Hand Continental,3.42's. 1968 Pontiac GTO : 11.114 @ 120.130 MPH New combo: 517 MR-1,10.8 CR,SD 350CFM E's,QFT 950/Northwind,246/252 HR,9.5” 4000 stall,3.42's 636HP/654TQ 1.452 10.603 @ 125.09 http://www.dragtimes.com/Pontiac-GTO...lip-31594.html |
#15
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Your secondary idle circuit holes are there, how about in the gasket being used?
Note, some very small amount of idle air should be passing thru the secondary’s throttle blades , maybe to the tune of being able to bring up the idle rpm by like 50, which if the carbs air bleeds are sized good for the motor will allow that added 50 rpm to be backed out of the primary without making for a off idle stumble. Sorry for the run on sentence!
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I do stuff for reasons. |
#16
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Yes, gasket has holes for idle circuit.
Thank you |
#17
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Secondary metering block hole
Can you tell me if what seems like someone took a screwdriver and punched this hole in the secondary main body? Should that gash be there?
Quote:
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#18
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Does that pass thru all the way into one of the throttle bores?
It's hard to tell from the photo! The answer is no, there should be no hole from the power valve recess cave into the throttle Bore.
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I do stuff for reasons. |
#19
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Quote:
to get the idle speed you want. I normally start with the blades a few thousands of a inch from seated. The "smashed in" casting "modification" says the carb was touched by a real "hack job" person and that "modification" needs to be filled with Devcon or a similar material to repair that mess. But it might not be repairable if there are other "unseen" similar mods. Tom V.
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"Engineers do stuff for reasons" Tom Vaught Despite small distractions, there are those who will go Forward, Learning, Sharing Knowledge, Doing what they can to help others move forward. |
#20
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Yes Tom sorry, meant .040. I sprayed carb cleaner into the smashed hole and it sprayed out the bottom. So that's amazing- that has to be my problem, and to your point, hopefully the only one.
Should I try this? https://www.jbweld.com/product/tankweld Thank you all |
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