4150 750 double pumper ,no adjustments?
#121886
09/16/08 07:34 PM
09/16/08 07:34 PM
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Joined: Mar 2007
Posts: 38
fort knox ky
440 trucknduster
OP
member
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OP
member
Joined: Mar 2007
Posts: 38
fort knox ky
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hi all, got a 60 over 440 with a holley double pumper with four corner idle. i have no adjustment on the idle screws? can screw them all the way in and nothing happins? jets are 84 up front, 73 in the rear,the car is running rich,real rich? any ideas on what is wrong? please help 
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Re: 4150 750 double pumper ,no adjustments?
[Re: 440 trucknduster]
#121893
09/16/08 08:27 PM
09/16/08 08:27 PM
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Joined: Jan 2003
Posts: 2,734
Charlotte, NC
446acuda
master
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master
Joined: Jan 2003
Posts: 2,734
Charlotte, NC
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Quote:
hi all, got a 60 over 440 with a holley double pumper with four corner idle.
i have no adjustment on the idle screws? can screw them all the way in and nothing happins? jets are 84 up front, 73 in the rear,the car is running rich,real rich?
any ideas on what is wrong? please help
What cam and how much initial timing? It might be tough to close the throttle plates without the engine stalling if you have a lot of cam and not enough initial timing.
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Re: 4150 750 double pumper ,no adjustments?
[Re: 440 trucknduster]
#121894
09/16/08 09:19 PM
09/16/08 09:19 PM
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Joined: Jul 2007
Posts: 531
Virginia
JimG
mopar
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mopar
Joined: Jul 2007
Posts: 531
Virginia
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AndyF and CudaJohn are correct.
If you don't have a vacuum leak or or a problem with the carb, I'm guessing you've cranked open the curb idle screw to get the idle RPM you want.
Take tha carb off and flip it over. Look at the primary throttle plates. The 2 transition slots are, well, they're slots that are ~ .200 - .250 long. As each throttle plate opens, it uncovers more of the slot, as they close, they cover more of the slot.
I'm guessing that to get the idle RPM you want, you've got too much of the slot uncovered. When the throttle plates are closed to curb idle, you should only see enough of the transition slot that it looks like a square. If you're seeing a rectangle, that's too much.
The cure is to drill small holes in the throttle plates so you can close the curb idle to get the proper plate/slot relationship.
Jim
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Re: 4150 750 double pumper ,no adjustments?
[Re: 440 trucknduster]
#121895
09/16/08 09:33 PM
09/16/08 09:33 PM
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Joined: Jul 2007
Posts: 531
Virginia
JimG
mopar
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mopar
Joined: Jul 2007
Posts: 531
Virginia
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Quote:
jets are 84 up front, 73 in the rear,the car is running rich,real rich?
Oh, and not that this has anything to do with your problem, but how did you end up with 84 jet in the primary and 73 in the secondry? 
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Re: 4150 750 double pumper ,no adjustments?
[Re: JimG]
#121896
09/16/08 09:39 PM
09/16/08 09:39 PM
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Joined: Nov 2007
Posts: 21,823
Kirkland, Washington
Pacnorthcuda
Too Many Posts
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Too Many Posts
Joined: Nov 2007
Posts: 21,823
Kirkland, Washington
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Quote:
AndyF and CudaJohn are correct.
The cure is to drill small holes in the throttle plates so you can close the curb idle to get the proper plate/slot relationship.
Jim
Easy there buddy...not too fast. Look at the posts above and read carefully. ADJUST the plate stop before drilling holes. Carefully read whats posted above.
I bet Holley likes you!!!
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Re: 4150 750 double pumper ,no adjustments?
[Re: 440 trucknduster]
#121897
09/17/08 07:28 AM
09/17/08 07:28 AM
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Joined: Jan 2003
Posts: 1,043
Slidell, La.
doctor_mopar
super stock
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super stock
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Posts: 1,043
Slidell, La.
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It is also possible that if your ignition timing is not advanced far enough , you may be having to open the throttle too much with your trying to get a high enough idle speed, and thus the carb is not in the position for the idle circuit to work. Check your timing ! You may need 10 to 15 degrees advance at idle speed. I doubt that you need to drill the throttle blades ! First, If it is real rich, you may have a needle and seat with debris holding it open or too high fuel pressure. You need to set float levels with it running see if fuel is at bottom of sight holes !
------------------------ It doesn't matter what you do.........As long as you look good doing it !
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Re: 4150 750 double pumper ,no adjustments?
[Re: doctor_mopar]
#121898
09/17/08 08:02 AM
09/17/08 08:02 AM
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Joined: Jan 2003
Posts: 9,982
Ansonia, CT
CJK440
master
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master
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Posts: 9,982
Ansonia, CT
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You can give the secondary throtte stop screw a crank in leiu of drilling holes.
I'd start by backing out the idle mixture screws 3 turns each. Fire up the car and back out the idle stop screw to try to get the car to the idle RPM you want then get back to us.
Check base timing while you are at it. Make sure the vacuum advance is disconnected and plugged.
2017 Contusion Blue Challenger T/A 392 M6 "BLKNBLU"
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Re: 4150 750 double pumper ,no adjustments?
[Re: 440 trucknduster]
#121899
09/17/08 01:25 PM
09/17/08 01:25 PM
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Joined: Jan 2003
Posts: 4,720
Moved to N.E. Tennessee
GomangoCuda
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Moved to N.E. Tennessee
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Quote:
jets are 84 up front, 73 in the rear
Quote:
Oh, and not that this has anything to do with your problem, but how did you end up with 84 jet in the primary and 73 in the secondry?
Your primary and secondary jets are swapped. I bet when you had it apart you switched the metering blocks. The one with the power valve and the 73 jets goes in the front. This could be your whole problem.
** IMPORTANT - Before you try anything else, Pull the fuel bowls off and make sure the Metering blocks are not switched.
Quote:
i have put a 2 and half power valve in it and new base plate gaskets ,havent opened the carb its self,
Wrong Powervalve unless you have a really huge camshaft or a really bad vacuum leak.
Quote:
What cam and how much initial timing? It might be tough to close the throttle plates without the engine stalling if you have a lot of cam and not enough initial timing.
I couldn't agree more.
1. We need to know more about the engine combo.
2. Most of the time more initial timing cures these "carb" problems. You will have to shorten the advance curve so that you can have enough initial without having too much total.
3. The info in the earlier posts about the mixture screws,transfer slots, and idle speed screws is good. You probably will not need to drill any holes. Set both of the idle speed screws so that the correct amount of transfer slot is exposed (as mentioned square is good). Put everything back together and start it up. For now resist the urge to mess with the idle speed screws. Adjust the timing to get the idle speed up where it belongs. Check the timing and see if it is reasonable (16-20degrees should be enough at idle). Now try to adjust the mixture screws. I bet they work now. Only use the idle speed screws to make very minor adjustments, remember you are trying to keep the transfer slots approximately square. You will probably need to shorten the advance curve to limit the total advance to around 36 degees. How you do this depends on your distributor.
In theory, there is no difference between theory and practice. In practice, there is.
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Happens a lot on Holleys. Close down the throttle plate, If it becomes hard to start then play with the idle screws...Also what NITROUSN said (check those first).