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Author
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Topic: holley 600 idle adjustment
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chips67
Gearhead Posts: 431
From: louisville, ky, usa
Registered: Jul 2001
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posted 11-25-2001 01:12 PM
   
ok, today i was trying to get the carb to quit loading up with fuel at idle (rich) so i started turning the idle/air adjustment screws in....lo and behold i turned both sides in till they stopped and the thing still idled the same! i rechecked the float levels and found the secondary side way high. i adjusted it down and the thing strted running rough with the idle/air screws in so i knew i was moving in the right direction. well, after all that the thing will still idle smoothly with the screws only 1/2 turn apiece out...what gives? i was thinking at least 1 1/2 turns out each side would be normal but only 1/2 turn? there are no vaccuum leaks, pv is a 4.5....any ideas guys?------------------
67 coupe, 650dp and rpm intake on 5.0 with afr 165 heads, 4 speed, 4.11's.....best so far is [email protected] in 1/8 mile with 1.79 60ft. time.
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bluestreek
Gearhead Posts: 485
From: Athens,GA
Registered: Jul 2001
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posted 11-25-2001 01:33 PM
When the idle mixture screws don't make much difference it usually means that the secondary plates are open a little too much. Try closing the secondary plates with the little adjusting screw that is hidden underneath the left rear of the throttle body. It can be almost completely closed but not binding in the bore.. If it is too rich after this, then you can also put a small guage piece of wire in each of the brass idle jets inside of the primary block to lean it back a little.. But you will need to use the choke to make it run better when the engine is cold.. The stock carbs have a custom metering system for the exact engine, but standard Holleys are usually setup for the average 350-400 c.i.. I have spent days tuning a standard Holley for a 289/302.. 
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chips67
Gearhead Posts: 431
From: louisville, ky, usa
Registered: Jul 2001
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posted 11-25-2001 07:15 PM
ok, you might be right. since i cracked the original baseplate and had to put on a new one, i remember ajusting that secondary screw till i could see a little light all around the plates when closed...maybe i opened them too much. i remember reading somewhere that this would increase throttle response. will have to back it off...i think that means taking the carb off....oh well, buy another gasket.------------------
67 coupe, 650dp and rpm intake on 5.0 with afr 165 heads, 4 speed, 4.11's.....best so far is [email protected] in 1/8 mile with 1.79 60ft. time.
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n2oMike
Gearhead Posts: 567
From: Spencer, WV
Registered: Jan 2001
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posted 11-25-2001 09:03 PM
The idle screws not making much difference can also be caused by a vacuum leak.------------------
Mike Burch
66 mustang real street
302 4-speed 289 heads
10.63 @ 129.3
http://www.geocities.com/carbedstangs/cmml_mburch.html
http://www.fortunecity.com/silverstone/healey/367
IP: Logged |
chips67
Gearhead Posts: 431
From: louisville, ky, usa
Registered: Jul 2001
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posted 11-25-2001 09:11 PM
ok, i did what was recomended and voila....nothing! actually i had to turn up the idle adjusting screw on the primary side to make up the difference of what i backed off the secondary side throttle blades, thats about it. n2o mike, there is no vaccuum leak. i promise there isnt. i know with a vac. leak you usually have exccessive tip in on the throtttle just to get it to idle and it runs lean/hot....went threw all this last week when the guts fell out of the pcv valve and had massive vac. leak. anyway, too tired to go back out tonight, see what happens tommorrow.------------------
67 coupe, 650dp and rpm intake on 5.0 with afr 165 heads, 4 speed, 4.11's.....best so far is [email protected] in 1/8 mile with 1.79 60ft. time.
IP: Logged |
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