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#1 |
Registered User
Join Date: Jan 2005
Location: Clearlake Oaks CA
Posts: 1,716
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Idle is low
Hi guys! Have been busy with my move from Northern Ca down to SO CAL. My question is with my 72 Short Fleet. It was idiling fine. I had it shipped down here. Upon starting it up, it seems to be idiling about 150-200 RPMS too low. Its around 500 RPM in Park and drops down to about 400-450 in Drive.To the point where it starts to load up. Now the ONLY thing that has changed is the Elevation. I WAS at 3200' and now I'm at about 200'. Its an Edelbrock Carb that was just rebuilt about a year ago and has less than 500 Miles on that rebuild. Everyrthing else is fine. There is no missing, rough Idiling ect. Just wanted to get your thoughts before I upped the idle. Roger
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Hello members... I'd like you to know that I sold, my 72 GMC (Ratikle), back in November of 2011. I don't visit the site much anymore, but please feel free, to drop me a private message. RIP...."RATIKLE" |
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#2 |
Registered User
![]() Join Date: May 2007
Location: Rapid City South Dakota
Posts: 2,359
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Re: Idle is low
Elevation will definitely be a factor. If your carb was in perfect tune before, it will be lean now. If you look in the Edelbrock carb manual, it will have an altitude formula. For every 1000 feet of change, you have to go richer or leaner, by a certain %. Most aftermarket carbs when new, are calibrated at sea level.
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#3 |
Registered User
Join Date: Oct 2007
Location: Spanaway
Posts: 8,451
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Re: Idle is low
Temprature change and relative humidity can also affect the tune of the carb, if its warmer and dryer then its running a little richer than it was before, that can lower the idle a bit. I'd say its just time for a good tune up.
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Mike. Swamp Rat build thread : http://67-72chevytrucks.com/vboard/s...d.php?t=595019 72 3/4T 4X4 4" BDS Lift 33" BFG's |
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#4 |
Registered User
Join Date: Jan 2005
Location: Clearlake Oaks CA
Posts: 1,716
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Re: Idle is low
Thanks guys!
Heres a kicker. Yesterday the guy comes to install my Internet. I back the Truck out (low idle) and all. Then I go to move it back in. I start it up and put it in gear., (it almost dies) so I give it some gas. When I did, IU got this small backfire out the exhaust. Then the Idle JUMPS UP to about 1200RPM. At this point, I'm power Braking it, so it doesnt run into the Garage. I put it in Park, and hit the Gas fast (to kick it down). It does, and now it runs/idles PERFECTLY, jusyt like it always has!!! ![]()
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Hello members... I'd like you to know that I sold, my 72 GMC (Ratikle), back in November of 2011. I don't visit the site much anymore, but please feel free, to drop me a private message. RIP...."RATIKLE" |
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#5 |
Registered User
Join Date: Dec 2010
Location: Arkansas
Posts: 608
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Re: Idle is low
Check your return spring on your throttle linkage.
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#6 |
Registered User
Join Date: Jan 2008
Location: MT
Posts: 85
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Re: Idle is low
...And check your fuel filter and clean your carb out.
A dot of oil on the throttle control linkage joints couldn't hurt. It sounds a bit sticky, make sure nothing is binding on the linkage or carb. Michael |
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#7 |
Registered User
Join Date: Oct 2007
Location: Spanaway
Posts: 8,451
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Re: Idle is low
Then i would be checking the choke linkage not the throttle linkage, it soulds like it may be stuck or binding, 1200 is a normal high rpm when the choke is activated. Well actually i guess i'd be checking everything in the process but i suspect the choke linkage forst.
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Mike. Swamp Rat build thread : http://67-72chevytrucks.com/vboard/s...d.php?t=595019 72 3/4T 4X4 4" BDS Lift 33" BFG's |
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#8 | |
Registered User
Join Date: Jan 2008
Location: MT
Posts: 85
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Re: Idle is low
Quote:
![]() Michael |
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#9 |
Registered User
Join Date: Jan 2005
Location: Clearlake Oaks CA
Posts: 1,716
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Re: Idle is low
I have some WD-40 Handy, can I use this in a bind?
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Hello members... I'd like you to know that I sold, my 72 GMC (Ratikle), back in November of 2011. I don't visit the site much anymore, but please feel free, to drop me a private message. RIP...."RATIKLE" |
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#10 |
Registered User
Join Date: Oct 2007
Location: Spanaway
Posts: 8,451
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Re: Idle is low
it won't hurt!
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Mike. Swamp Rat build thread : http://67-72chevytrucks.com/vboard/s...d.php?t=595019 72 3/4T 4X4 4" BDS Lift 33" BFG's |
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#11 |
Registered User
Join Date: Jan 2005
Location: Clearlake Oaks CA
Posts: 1,716
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Re: Idle is low
So heres a picture I took under my Hood of my Elebrock Carb.
Can anyone tell me if what I'm pointing at (and is Circled in White), is the Idle Speed screw?
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Hello members... I'd like you to know that I sold, my 72 GMC (Ratikle), back in November of 2011. I don't visit the site much anymore, but please feel free, to drop me a private message. RIP...."RATIKLE" |
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#12 |
Registered User
![]() Join Date: Dec 2010
Location: Paradise, ca
Posts: 295
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Re: Idle is low
I used to drive a car transport truck. if you had it shipped on a truck, I probably know what happened.
when your vehicle is tied down on a semi trailer, it manages to jar loose every bit of everything in the fuel system. you might have had some crud in the fuel bowl, or in the gas tank, or fuel line that broke loose during transit. I can not begin to count the number of classic vehicles that I loaded running perfectly, and unloaded running rough and back firing. yes altitude can cause problems, but it happened to me when it was picked up and dropped off at close to sea level. change the fuel filter just in case.
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![]() Last edited by Allensracing; 12-14-2010 at 02:45 PM. |
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#13 | |
Registered User
Join Date: Jan 2005
Location: Clearlake Oaks CA
Posts: 1,716
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Re: Idle is low
Quote:
My Truck was on a single enclosed trailer, by itself being towed by a Flatbed tow Truck. I'm sure there was some amount of Jarring, but not sure in comparison to a BIG Transport Hauler.
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Hello members... I'd like you to know that I sold, my 72 GMC (Ratikle), back in November of 2011. I don't visit the site much anymore, but please feel free, to drop me a private message. RIP...."RATIKLE" |
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#14 |
Registered User
![]() Join Date: Dec 2010
Location: Paradise, ca
Posts: 295
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Re: Idle is low
my hauler rode on airbags, and had very little jaring. it was more like being on a boat, a mutlidirection rocking. somehow it moved stuff around that normal driving did not do, yet i could leave half a soda on the floor and it wouldnt fall over after a thousand miles of driving.
I dont understand it, I just know it happened.
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#15 | |
Registered User
Join Date: Oct 2007
Location: Spanaway
Posts: 8,451
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Re: Idle is low
Quote:
The 2 screws on the front of the body close to the base of the carb are the air/fuel mix screws.
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Mike. Swamp Rat build thread : http://67-72chevytrucks.com/vboard/s...d.php?t=595019 72 3/4T 4X4 4" BDS Lift 33" BFG's |
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#16 | |
Registered User
Join Date: Jan 2005
Location: Clearlake Oaks CA
Posts: 1,716
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Re: Idle is low
Quote:
THANK YOU!!!!!!!!!! ![]()
__________________
Hello members... I'd like you to know that I sold, my 72 GMC (Ratikle), back in November of 2011. I don't visit the site much anymore, but please feel free, to drop me a private message. RIP...."RATIKLE" |
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