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Old 06-19-2003, 11:12 AM
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Any Holley carb gurus out there?

Ok here's the scoop. I searched and beat myself to death trying to find a cure or someone that has had a similiar problem. I bought a rebuilt Holley 650 DP off of Ebay and it had a new Kenny Belle kit installed. The carb looks clean and fairly new , but it will not idle stable. I am fairly familiar with Holleys , but this has me baffled. I have adjusted the floats and secondary blades to eliminate them as the culprit. The A/F adjustment has no bearing on the idle quality. I can hold my hand over the top of the air inlet and it will idle up and become stable which indicates a vacuum leak, but I have triple checked evrything with carb cleaner and there are NO leaks. I even installed my original Holley 600 VS and it idles like a dream so there is an internal problem somewhere. Any chance there is a power valve problem? I have 18 inches of vacuum at an idle and I have no idea which
PV it has in it. I have managed to idle it up enough to keep it running on its own , but it is idling very high rough and it surges horribly. I'd appreciate any suggetions. Thanks!!


James

Pasadena, Texas


1965 Comet 289 with bolt on mods.

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Old 06-20-2003, 06:37 AM
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Power valve problems usually create rich conditions or a lean pop on accelerating, not what your experiencing. You didn't say what # jets were in it, although that's probably not the problem. Because it was "rebuilt" before you got it, I suspect incorrect metering plate gaskets or similar. Some people don't realize there are several different type gaskets for the various Holleys. The other possibility is restricted passages. The fact that the mixture screws have no effect usually indicates passage problems or primary blades opened beyond the idle circuits, maybe you need to open the secondaries instead of closing them and back the primaries down. Hope this helps.
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Old 06-20-2003, 01:10 PM
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pm 36willys. how sure are you that your throttle rod is straight? thats the only thing i know of that will make a holley junk
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Old 06-20-2003, 08:17 PM
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You could pull the mixture screw out and try to blow the idle passages out. Might want to check and make sure the secondary throttle plates are not hanging open. There is a little screw in the throttle base that controls the stop on the scondary throttle plate. Make sure it is not screwed to tight keeping them open.
You may have picked up some dirt in the idle or cross over to the main metering systems. Holleys do not like DIRT.
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Old 06-20-2003, 08:48 PM
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Well I tried all of the above. I made sure the secondaries were not hanging open or cracked with the adjustment screw, I tried cracking open the secondaries via the adjustment screw and lowered the primary idle screw with no luck. I blew out the A/F adjutment holes and ran carb cleaner through them to confirm a clear path with no luck at all. It still idles very rough(almost like a pro stocker) and it is very slow to return to a low idle set point as if there is a vacuum leak present. I do have to question the throttle shaft possibility since I tried to adjust the rear butterflies to ensure a tight seal, there was no way to get an air tight seal when they are closed. Once I tighten them up, there is a very slight amount of clearance. I do appreciate everyones help. I am really tired of jacking with it. Please keep the ideas coming. TIA.


James
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Old 06-20-2003, 10:24 PM
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If you can't get the secondaries to shut tightly then loosen off the screws holding the throttle plates to the shaft and readjust the secondary idle stop until the plates fit tight in the bores then retighten the screws holding the plates to the throttle shafts.This should fix that little problem.Check that the throttle plates don't stick in the bores after this adjustment.
Next I would remove the bowls and metering blocks and take compressed air to the air passages at the bottom of the idle air bleads,blowing the air in and up and out of the idle air bleads that are just inside the air horn of the carb.If there's crud in the idle air bleads the idle quality will be real bad and adjusting the idle screws will do little to help.
The previous owner probably didn't use an air cleaner and the bleads sucked dirt in and pluged the emulsifier tubes under the air bleads.
then check that the correct gaskets are used and no ports are covered buy the gasket in the metering block and main body.reassembly the carb and readjust the accelerator pump linkage(this must be done every time the bowls are removed)and reinstall the carb.hopefully this will clear up the idle for you. Good luck.....happy HOLLEY-DAYS:p
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Old 06-20-2003, 10:44 PM
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secondaries

For mechanical secondaries
As far as the secondaries go, They should be cracked slightly. I use 2 660 center squirters and these are some pretty hands on carbs. Holleys have an air bleed hole in the venturi, as a rule if your secondary plates are past that hole your out of adjustment. The secondaries are craked a hair.
I also years ago had a problem of the same nature whith a 750 double pumper. I had to drill a hole in each of the plates to get more air to run through the secondaries so it would idle
For vacum secondaries holley has a spring kit. It sounds like theres a really light spring in their.
Augie
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Old 06-20-2003, 10:47 PM
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While you have the bowls off, check(test)the power valve. If the carb. set dry for a while, It`s very possable the gaskets shrunk
hollys are bad about that. Get new blue gaskets when you reassemble it. also check for up and down slack in the primary throttle shaft on drivers side. hth

Troy
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Old 06-21-2003, 12:56 AM
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Ok guys , I'll try one more time. I'll get a whole new rebuild kit and try the tip that you suggested. I just don't remember Holleys being so finicky. I'll keep you posted on the results. Again, I do appreciate your help.



James
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Old 06-21-2003, 07:30 AM
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Holleys have long been "finicky" that's why I usually recommend to people that don't do their own work to get an Edelbrock/Carter.
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Old 06-21-2003, 11:34 PM
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OK Guys I finally figured it out. After fighting with this thing for days , I managed to rule out all of the suggestions except for the shotgun option.

I found that the gasket between the base plate and main body was incorrect. It was a perfect match except for two outer holes that feed the primary idle A/F circuit. I still don't know if the kit came with a mixed up gasket or if the original rebuilder used the wrong kit, but it was definitely the culprit. I noticed that it didn't have holes to allow flow to these two passages so I stamped out holes to allow that flow and it purrs like a kitten. I will be doing a complete rebuild on it tomorrow with the RIGHT kit. I sure do appreciate all the help you guys offered. This was a tough one.

I hope this thread helps someone else in the future.


Take care.


James
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Old 06-22-2003, 07:26 AM
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TRY THESE THINGS

SOUNDS LIKE SIMILAR PROBLEMS IVE HAD IN THE PAST . LEAN IDLE. REMOVE THE METERING BLOCK LOOK AT THE IDLE PASSAGES EITHER SIDE OF THE POWER VALVE.TELL ME WHAT SIZE HOLES THEY ARE.ALSO TELL ME METERING BLOCK NUMBER POSS. SOMEONE AS SWAPPED IT GLAD TOHELP.
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Old 10-26-2004, 08:46 AM
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"You could pull the mixture screw out and try to blow the idle passages out."


This sounds like the best idea to me in this thread. I have an 1850 that is plagued with this same problem. When I tear it down and force 130 PCI through the idle circuits, it straightens up quite a bit, for awhile, but gradually gets worse again....a sure sign of a blockage, possibly even a bad casting. I haven't immersed it in carb cleaner for a week yet, but if I need another 600 vac. secondary, I'll probably try it before buying another carb.

Anyway, it doesn't sound like a power valve problem at all....incidentally, to determine the power valve you should have in your carb, check your vacuum at idle with the tranny in gear, divide by two and buy that PV. For example, if you're pulling 13 inches at idle in gear, you need a 65 power valve.

Also, pardon me if I state the obvious, or re-state answers that have been given on other threads. Brand new to this forum.
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Old 10-26-2004, 09:04 AM
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Welcome aboard stickman. When looking for a post to answer, you should check the dates. This thread was dead a year ago.

Troy

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Old 10-26-2004, 06:38 PM
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Ouch, almost a year and a half.......I guess I win "Horse's *** of the Week" award? Pretty cool, first post on a forum and I'm already winning stuff


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