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My Holley Idles Too High!!
#1242553
05/31/12 12:32 AM
05/31/12 12:32 AM
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Joined: Dec 2007
Posts: 486
IL
knyech1
OP
mopar
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OP
mopar
Joined: Dec 2007
Posts: 486
IL
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I can't seem to get my car to idle down. When I first got it running, it didn't want to stay running at all, would idle high and want to stall. Now it just wants to idle high and I didn't do anything to the carb yet. It idles at 1,400rpm in neutral, 1,100 in drive. The carburetor is a 4150 800 cfm double pumper #4780. Proform main body, no choke tower.
Specifics on the car (if it matters) are:
71 Demon may be around 2900#
340 stock stroke
275cfm iron heads
10.49:1 comp
904 trans w/TB
5500 stall
4.88 gears w/32" tires
So far I have pulled the float inspection screws, could see the fuel level.
Messing with the idle screw does nothing.
Messing with the mixture screws on the metering block does nothing. Does not have mixture screws on the rear metering block (don't know why?)
I sprayed carb cleaner around the intake, around the 1.5" spacer top and bottom, and all over the carb to check for a vacuum leak and the rpms stayed the same...right at 1,400rpm. All the vacuum ports on the carb are blocked.
I have no clue what to do here does anybody have any advice for me? I don't have much experience with Holleys, or carbs in general so I am not sure where to go from here and I am supposed to race in two days.
knyech1-
'71 Sassy Grass Demon 340/904. Pump gas, 1.61 60ft, 7.439 1/8 @ 95mph, 11.824 1/4 @ 111mph
"Not too bad for a pump gas 340, full of used parts and hillbilly ported stock heads." - V.B.
'03 2500 5.9L HO 6-spd on 35's. 395hp/755ft-lb at tires.
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Re: My Holley Idles Too High!!
[Re: knyech1]
#1242555
05/31/12 12:47 AM
05/31/12 12:47 AM
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Joined: Aug 2003
Posts: 8,716
Baltimore/Denver
64Post
master
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master
Joined: Aug 2003
Posts: 8,716
Baltimore/Denver
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There's a small screw that adjust the secondary throttle blades on the pass. side of the carb. You'll have to hold the arm wide open to adjust it. See if that's your problem.
Power valve?
Last edited by 64Post; 05/31/12 12:50 AM.
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Re: My Holley Idles Too High!!
[Re: Red440]
#1242560
05/31/12 02:00 AM
05/31/12 02:00 AM
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Joined: Dec 2007
Posts: 486
IL
knyech1
OP
mopar
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OP
mopar
Joined: Dec 2007
Posts: 486
IL
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Quote:
check for vacuum leaks, something maybe loose  carb, intake , carb spacer 
I sprayed the carb cleaner all over thinking that would expose the leak if there was one, but nothing happened. I will go check and see if something loosened up...  ...ok checked the carb and it was tight. Checked the intake for the 4th time now and actually 2 bolts were not quite torqued down. I say torqued down but I can't get a torque wrench on them (RPM Air Gap, the middle two bolts on either side). I tightened them up a bit. Would start the car now, but it's midnight and I don't want to have the police called on me...again. Neighbors don't like young whippersnappers like me having loud cars, trucks and bikes  
Will start it tomorrow and let you all know what happens.
knyech1-
'71 Sassy Grass Demon 340/904. Pump gas, 1.61 60ft, 7.439 1/8 @ 95mph, 11.824 1/4 @ 111mph
"Not too bad for a pump gas 340, full of used parts and hillbilly ported stock heads." - V.B.
'03 2500 5.9L HO 6-spd on 35's. 395hp/755ft-lb at tires.
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Re: My Holley Idles Too High!!
[Re: RobX4406]
#1242562
05/31/12 02:10 AM
05/31/12 02:10 AM
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Joined: Jan 2004
Posts: 13,247
Mt. Vernon, Ohio
dartman366
I Live Here
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I Live Here
Joined: Jan 2004
Posts: 13,247
Mt. Vernon, Ohio
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Idle ajustment screw on the primary's that would also explain the no response out of the idle quality screws, I would take it off and reset the throttle blades and make sure they are set right with the idle transferr slots in the base plate and check for any mechanical interference, could also be an internal vacuum leak also that wouldn't show up with the carb cleaner trick. was there a vacuum hose left off some where, also does it have power brakes, maybe a faulty booster. I'm still thinking 
Light travels faster than the speed of sound,,,this is why some people seem bright untill you hear them speak.
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Re: My Holley Idles Too High!!
[Re: dartman366]
#1242565
05/31/12 02:15 AM
05/31/12 02:15 AM
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Joined: Dec 2007
Posts: 486
IL
knyech1
OP
mopar
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OP
mopar
Joined: Dec 2007
Posts: 486
IL
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Quote:
Idle ajustment screw on the primary's that would also explain the no response out of the idle quality screws, I would take it off and reset the throttle blades and make sure they are set right with the idle transferr slots in the base plate and check for any mechanical interference, could also be an internal vacuum leak also that wouldn't show up with the carb cleaner trick. was there a vacuum hose left off some where, also does it have power brakes, maybe a faulty booster. I'm still thinking
I will double check for missing vacuum hoses, but they should all be blocked off. I have manual brakes :/
How can I reset the throttle blades? Please bear with me I am kind of carb dumb, didn't know the throttle blades could be reset.
knyech1-
'71 Sassy Grass Demon 340/904. Pump gas, 1.61 60ft, 7.439 1/8 @ 95mph, 11.824 1/4 @ 111mph
"Not too bad for a pump gas 340, full of used parts and hillbilly ported stock heads." - V.B.
'03 2500 5.9L HO 6-spd on 35's. 395hp/755ft-lb at tires.
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Re: My Holley Idles Too High!!
[Re: knyech1]
#1242568
05/31/12 02:21 AM
05/31/12 02:21 AM
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Joined: Apr 2005
Posts: 12,271
Overpriced Housing Central
RobX4406
I Live Here
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I Live Here
Joined: Apr 2005
Posts: 12,271
Overpriced Housing Central
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Quote:
Quote:
Should be able to idle that down to the 950-1000 range if everything is right.
I'll say I'd put about 20-22 initial timing on it. That's where my 340 with a 528 mechanical wanted it.
Rebel and RobX, I am not sure how to set initial timing I guess. I thought initial timing had to be set below 1,000rpm and above that your distributor started to advance...I guess I may be wrong. If I am I could tell you what I have it set at tomorrow probably. IIRC I tried to set it at 23deg.
As long as it's not bleeding in mechanical advance at idle, you're setting initial. Don't worry about total at this point. Not sure why you are having trouble seeing it. Pretty easy unless you have a chrome damper or no marks to reference.
23 initial, if correct, is a decent starting point for that set up IMO.
If using a stock damper, hillbilly timing tape it.
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Re: My Holley Idles Too High!!
[Re: knyech1]
#1242569
05/31/12 02:26 AM
05/31/12 02:26 AM
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Joined: Jan 2004
Posts: 13,247
Mt. Vernon, Ohio
dartman366
I Live Here
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I Live Here
Joined: Jan 2004
Posts: 13,247
Mt. Vernon, Ohio
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Quote:
Quote:
Should be able to idle that down to the 950-1000 range if everything is right.
I'll say I'd put about 20-22 initial timing on it. That's where my 340 with a 528 mechanical wanted it.
Rebel and RobX, I am not sure how to set initial timing I guess. I thought initial timing had to be set below 1,000rpm and above that your distributor started to advance...I guess I may be wrong. If I am I could tell you what I have it set at tomorrow probably. IIRC I tried to set it at 23deg.
It should be set at idle, but thats the problem,,can you check the total to see that you are not out of the ballpark with it by having way too much? lot's of times I have seen too much timing cause a high idle, maybe not as much as yours but elevated.
Light travels faster than the speed of sound,,,this is why some people seem bright untill you hear them speak.
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Re: My Holley Idles Too High!!
[Re: dartman366]
#1242570
05/31/12 07:15 AM
05/31/12 07:15 AM
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Joined: Dec 2004
Posts: 1,489
St. Louis Mo.
10 o to go
"Happy Don"
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"Happy Don"
Joined: Dec 2004
Posts: 1,489
St. Louis Mo.
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Check your Dist could be advance springs stuck .I didn't see what dist you had does it have a vac advance ? Turn the Sec screw you will have to have a wierd screwdriver Home made to go up to that screw shut the butterfly more . One ?? when you rev it ,does it come back down ? 
Last edited by 10 o to go; 05/31/12 07:16 AM.
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Re: My Holley Idles Too High!!
[Re: RobX4406]
#1242571
05/31/12 09:28 AM
05/31/12 09:28 AM
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Joined: Dec 2007
Posts: 486
IL
knyech1
OP
mopar
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OP
mopar
Joined: Dec 2007
Posts: 486
IL
|
Quote:
Quote:
Quote:
Should be able to idle that down to the 950-1000 range if everything is right.
I'll say I'd put about 20-22 initial timing on it. That's where my 340 with a 528 mechanical wanted it.
Rebel and RobX, I am not sure how to set initial timing I guess. I thought initial timing had to be set below 1,000rpm and above that your distributor started to advance...I guess I may be wrong. If I am I could tell you what I have it set at tomorrow probably. IIRC I tried to set it at 23deg.
As long as it's not bleeding in mechanical advance at idle, you're setting initial. Don't worry about total at this point. Not sure why you are having trouble seeing it. Pretty easy unless you have a chrome damper or no marks to reference.
23 initial, if correct, is a decent starting point for that set up IMO.
If using a stock damper, hillbilly timing tape it.
Its a nice shiny SFI damper from Summit and it is kind of difficult to read. I will do it in the garage this afternoon and see what it says.
dartman366, how high do I need to have the rpms to make sure I am reading total timing and what should that number be?
10 o to go, my distributor is a factory electronic with vacuum advance, BUT I have the vacuum line blocked off.
When I rev it up it comes right back to 1,400rpm 
knyech1-
'71 Sassy Grass Demon 340/904. Pump gas, 1.61 60ft, 7.439 1/8 @ 95mph, 11.824 1/4 @ 111mph
"Not too bad for a pump gas 340, full of used parts and hillbilly ported stock heads." - V.B.
'03 2500 5.9L HO 6-spd on 35's. 395hp/755ft-lb at tires.
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Re: My Holley Idles Too High!!
[Re: knyech1]
#1242572
05/31/12 09:43 AM
05/31/12 09:43 AM
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Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY
Master
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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Quote:
Quote:
Quote:
Quote:
Should be able to idle that down to the 950-1000 range if everything is right.
I'll say I'd put about 20-22 initial timing on it. That's where my 340 with a 528 mechanical wanted it.
Rebel and RobX, I am not sure how to set initial timing I guess. I thought initial timing had to be set below 1,000rpm and above that your distributor started to advance...I guess I may be wrong. If I am I could tell you what I have it set at tomorrow probably. IIRC I tried to set it at 23deg.
As long as it's not bleeding in mechanical advance at idle, you're setting initial. Don't worry about total at this point. Not sure why you are having trouble seeing it. Pretty easy unless you have a chrome damper or no marks to reference.
23 initial, if correct, is a decent starting point for that set up IMO.
If using a stock damper, hillbilly timing tape it.
Its a nice shiny SFI damper from Summit and it is kind of difficult to read. I will do it in the garage this afternoon and see what it says.
dartman366, how high do I need to have the rpms to make sure I am reading total timing and what should that number be?
10 o to go, my distributor is a factory electronic with vacuum advance, BUT I have the vacuum line blocked off.
When I rev it up it comes right back to 1,400rpm
Get it up to 3000rpm to set the total timing...34*
should be close for testing... then you can tweek
it in on the track.... if it drops right back to 1400
it sounds like its a mech issue... check the secondary
screw to see if its too high.... IF you want to pull
the carb off to set the transfer slot you can...
once its off flip it over(gas will pour out) and
look at the slot at the throttle blades....set the
throttle so that the slot makes a square hole...
if the blades are open too far you are past the idle
circuit so the idle mixture screws wont have any
effect... so get it down on the idle then mess with
the mixture and idle set screw...... you said that
the throttle cable has some slack so that MOST LIKELY
isnt the issue... check the secondary screw... timing
comes first though... then the carb
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