loaner carb problems(lars??)
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Drifting
Joined: Aug 2001
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From: North Carolina
loaner carb problems(lars??)
the throttle linkage doesn't drop back to the idle screw, which is making my idle rpm sky rocket, and never drop back down. The idle screw has to be more then half way in to even touch to linkage. On MY carb, the screw just has to be out like 3 threads before it touches the linkage, on my loaner carb, it has to be about 8 or 9(I guess)...anyway, its a huge distance. what gives?
Daniel
Daniel
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Drifting
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From: North Carolina
Re: loaner carb problems(lars??) (A C)
Do you have the throttle return spring on? :D
AC
AC
I put my old carb back on, and its still racing. My dad keeps telling me to let it go until it warms up, but the RPM's are so high I think it'd blow up before it warms up. My tach is broken, but to put it into perspective, the RPM's are higher then when I took it up to 90 MPH a few months ago...I KNOW that can't be the right warm up RPM. My problem is somewhere else(not the carb).
Daniel
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Drifting
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From: North Carolina
Re: loaner carb problems(lars??) (daniel77350)
What Im going to do, is take it to a mechanic, and let him charge me an arm and a leg to fix something I have over looked. For someone who doesn't get mad easily(me), this car makes me furious. :mad It likes to develop problems only when I want to drive it. As for fixing it being half the fun...I agree, the other half of the fun is driving it. However, when you can never drive it, because your always fixing problems, it a bit of a catch 22...
Daniel
Daniel
Burning Brakes
Joined: Dec 1999
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From: Saskatoon Saskatchewan Canada
Re: loaner carb problems(lars??) (daniel77350)
It's not just stuck on the fast idle cam is it ? ck on the right side of carb. If the box got turned upside down when shipped it could easily of put it on the little cam.
Pro
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From: Now Frozen in Michigan
Re: loaner carb problems(lars??) (daniel77350)
Dan-
Could be that the choke is engaging the fast idle cam. On a Q-Jet, reach behind the choke (coil) housing and push the (usually lt grn color) tab downward. (while just cracking the throttle a touch) This will force the choke to disengage until the throttle is opened some again. (or until the choke warms enough to disengage) If this works, try adj the 'fast idle' screw on the choke linkage (side) with tach inst to approx 1500 RPM's with the screw on the 'highest' step of the cam.
Also check that there are no obstructions, and the linkage is not binding and has free travel (choke included).
And try (with eng off, of course) looking w/light into carb bores to be sure the throttle plates are not binding while moving throttle.
Hope this helps get ya running before the weather warms...Good Luck -Rod :chevy
Could be that the choke is engaging the fast idle cam. On a Q-Jet, reach behind the choke (coil) housing and push the (usually lt grn color) tab downward. (while just cracking the throttle a touch) This will force the choke to disengage until the throttle is opened some again. (or until the choke warms enough to disengage) If this works, try adj the 'fast idle' screw on the choke linkage (side) with tach inst to approx 1500 RPM's with the screw on the 'highest' step of the cam.
Also check that there are no obstructions, and the linkage is not binding and has free travel (choke included).
And try (with eng off, of course) looking w/light into carb bores to be sure the throttle plates are not binding while moving throttle.
Hope this helps get ya running before the weather warms...Good Luck -Rod :chevy
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Re: loaner carb problems(lars??) (daniel77350)
Daniel, make sure the "fast step idle cam" on the passenger side of the carb is'nt stuck in the "fast idle" position. This is that little swinging pendulum, that when stuck up will result in fast idling. As the car is warming up and the choke plate opens, it will "fall" taking the car down to the idle set on the left side idle screw. With the car off, and fully warmed up, make sure this weighted pendulum falls all the way or your car will idle high!!!
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Drifting
Joined: Oct 2000
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From: Shawano WI
Re: loaner carb problems(lars??) (daniel77350)
If you cannot push it close with your hand one of two thing is holding it open. Either the throttle cable or the fast idle cam. Hold the choke open manually, then work the throttle and see it it returns to idle.
Also if tyou put your old carb on and it is racing also are you sure you don't have a vacumm leak? Possible a hose not plugged in?
Also if tyou put your old carb on and it is racing also are you sure you don't have a vacumm leak? Possible a hose not plugged in?
Thread Starter
Drifting
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From: North Carolina
Re: loaner carb problems(lars??) (Pete79L82)
if I push the fast idle down, the throttle returns to the set screw, as soon as I move the torttle, as if I where to touch the trottle to accelerate, it moves back out and gets stuck about 8-9 threads away from the screw..which puts my in the same exact place with the same problem.
Daniel
Daniel
Burning Brakes
Joined: Dec 1999
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From: Saskatoon Saskatchewan Canada
Re: loaner carb problems(lars??) (Pete79L82)
That is the way it is suppose to work until it warms up. Then the cam will stay down by itself.
Pro
Joined: Jul 2000
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From: Now Frozen in Michigan
Re: loaner carb problems(lars??) (daniel77350)
Dan-
Exactly. Read above again...sounds if the choke is engaging. It will stay engaged until the engine warms up to op temp. There's a bi-metal coil spring encased in the choke housing. When cold, it winds-up creating tension to move/engage the choke linkage. This in turn also moves a 'fast idle' cam into position to take control of the idle setting (faster) until warm-up occurs. When you first stab the throttle to cold start, this allows the choke coil tension to activate. This will repeat everytime you 'crack' the throttle when cold. Does this help clarify?.....-Rod :chevy
Exactly. Read above again...sounds if the choke is engaging. It will stay engaged until the engine warms up to op temp. There's a bi-metal coil spring encased in the choke housing. When cold, it winds-up creating tension to move/engage the choke linkage. This in turn also moves a 'fast idle' cam into position to take control of the idle setting (faster) until warm-up occurs. When you first stab the throttle to cold start, this allows the choke coil tension to activate. This will repeat everytime you 'crack' the throttle when cold. Does this help clarify?.....-Rod :chevy
Thread Starter
Drifting
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From: North Carolina
Re: loaner carb problems(lars??) (ROD NOCK)
but are the warm up idles really that "racy"??
I mean the last time the thing idled this high, I was revving it so a friend could hear the exhaust note....that doesn't seem correct.
Daniel
I mean the last time the thing idled this high, I was revving it so a friend could hear the exhaust note....that doesn't seem correct.
Daniel
Tech Contributor
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From: At my Bar drinking and wrenching in Lafayette Colorado
Re: loaner carb problems(lars??) (daniel77350)
Daniel -
Most likely, your throttle linkage is not adjusted right. Disconnect your throttle cable and the idle should be fine. Re-adjust the cable so it is not holding the throttle open.
The fast idle on that carb was set up to idle at 1500 rpm with a cold engine - it was tested before the carb was shipped. If the cable is not the culprit and the fast idle is, in fact, too high for you, simply back off the fast idle screw as outlined in the carb tuning instructions included with the carb. Contact me if you need any help.
[Modified by lars, 10:24 PM 3/22/2002]
[Modified by lars, 10:30 PM 3/22/2002]
Most likely, your throttle linkage is not adjusted right. Disconnect your throttle cable and the idle should be fine. Re-adjust the cable so it is not holding the throttle open.
The fast idle on that carb was set up to idle at 1500 rpm with a cold engine - it was tested before the carb was shipped. If the cable is not the culprit and the fast idle is, in fact, too high for you, simply back off the fast idle screw as outlined in the carb tuning instructions included with the carb. Contact me if you need any help.
[Modified by lars, 10:24 PM 3/22/2002]
[Modified by lars, 10:30 PM 3/22/2002]
Le Mans Master
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Re: loaner carb problems(lars??) (lars)
Daniel -
Most likely, your throttle linkage is not adjusted right. Disconnect your throttle cable and the idle should be fine. Re-adjust the cable so it is not holding the throttle open.
Most likely, your throttle linkage is not adjusted right. Disconnect your throttle cable and the idle should be fine. Re-adjust the cable so it is not holding the throttle open.
Tech Contributor
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From: At my Bar drinking and wrenching in Lafayette Colorado
Re: loaner carb problems(lars??) (lars)
Another thought for you, Daniel -
If you'd like to eliminate the choke & fast idle function altogether, simply loosen the 3 screws that hold the big, round, black choke cover in place. Once the screws are nice and loose, you can rotate the cover clockwise about 1/2 turn and snug the screws back up. This will lock the choke in the full open position, and the fast idle function will be eliminated.
The fast idle was set up in a Pontiac 455 engine. It could be that your small block requires less throttle opening when cold to stay running, so feel free to adjust the fast idle screw mentioned earlier. It's a regular slotted head screw on the passenger side of the carb, so just take your screwdriver to it and back it out about one turn. This all assumes, of course, that you have eliminated the throttle cable as being the problem....
If you'd like to eliminate the choke & fast idle function altogether, simply loosen the 3 screws that hold the big, round, black choke cover in place. Once the screws are nice and loose, you can rotate the cover clockwise about 1/2 turn and snug the screws back up. This will lock the choke in the full open position, and the fast idle function will be eliminated.
The fast idle was set up in a Pontiac 455 engine. It could be that your small block requires less throttle opening when cold to stay running, so feel free to adjust the fast idle screw mentioned earlier. It's a regular slotted head screw on the passenger side of the carb, so just take your screwdriver to it and back it out about one turn. This all assumes, of course, that you have eliminated the throttle cable as being the problem....