proper carb adjustment steps - The 1947 - Present Chevrolet & GMC Truck Message Board Network

shelby987 · 06-02-2006, 07:44 PM

For those of you following my previous saga, my rebuilt economaster carb is on now on my truck and running very well, but I am having difficulties adjusting the carb, the holley manual is not very helpful (it references smog equipment that my truck obviously does not use).

I have tried to set the idle using the idle screw on the throttle level, when it starts it runs at 2k, if I turn it down it won't make much change until it gets to a point where it will stall out. I thought maybe I needed to wait until the engine was warm, so I waited until the engine hit operating temp, turned down the idle screw, and got the engine to just below 1k....but if I rev up the engine a couple of times, when it goes back to idle, it sits at between 1,600 and 2,000 rpm again.

I thought maybe I needed to adjust it via the mixture screws from there....and I seem to be chasing my tail.....what are the proper steps to set the idle and mixture screws????

*rage'nrat638* · 06-02-2006, 10:21 PM

man if it was not for bad luck you would not have any luck at all...

sounds like my luck as of late..
please don't take this personal. all info to follow is just my opinion...

sounds like your still dealing with a leak at the intake runner or with the carb it self. or the spacers you got the carb mounted with.

this is what makes the carb idle all over the place.
with the spacers and this carb you got..o-boy me , i am done with holley carbs. nuf said..

your going to have to start with a process of elimination. starting at the intake runners..re-tighten again. make sure you got the gaskets installed correct.
i would mount a correct carb..even a 2300 500 cfm holley carb would be better than the economaster carb. what ever it takes to get rid of the spacers.

i am the nicest guy in the world. and am only trying to lead you in the right direction. and i have read some of your other post and see your pulling your hair out here, trying to get this bad boy running correctly.

the problems you have right now..are more than a adjustment on the carb. this i can say with 100% confidence.
your pal mark

Karl Hoh · 06-03-2006, 02:56 AM

Man, I though you beat this thing. I agree with RageNRat, go over everything with wd-40 or carb cleaner to find the vacuum leak/leaks. It has to be able to idle controllably ( is that a word?) @ 600-800 rpm. If you get it, post, I'll explain how to set it. ( it's been a looong day & I'm too tired to type that much now.) Good luck.
Karl

zeeklu · 06-03-2006, 06:13 AM

http://www.bob2000.com/carb.htm Chris

06-02-2006, 07:44 PM	#1
shelby987 Registered User Join Date: Mar 2005 Location: Just outside Durham, NC Posts: 894	proper carb adjustment steps For those of you following my previous saga, my rebuilt economaster carb is on now on my truck and running very well, but I am having difficulties adjusting the carb, the holley manual is not very helpful (it references smog equipment that my truck obviously does not use). I have tried to set the idle using the idle screw on the throttle level, when it starts it runs at 2k, if I turn it down it won't make much change until it gets to a point where it will stall out. I thought maybe I needed to wait until the engine was warm, so I waited until the engine hit operating temp, turned down the idle screw, and got the engine to just below 1k....but if I rev up the engine a couple of times, when it goes back to idle, it sits at between 1,600 and 2,000 rpm again. I thought maybe I needed to adjust it via the mixture screws from there....and I seem to be chasing my tail.....what are the proper steps to set the idle and mixture screws???? __________________ 1969 SS 350 Camaro Sold 2008 1970 3/4T K20, stock height with 33's, 250 I6, 3 on the tree, and locked front and rear 4.10's 1980 Chevy Malibu 2 dr Sold 2007 1993 Olds. Cutlass Ciera Wagon Traded 2006 2003 Saturn L200 w/5pd. D/D My list spans 5 decades with One common thread.....GM!

06-02-2006, 10:21 PM	#2
rage'nrat638 Account Suspended Join Date: Mar 2003 Location: THE FALL GUY CHICAGO IL Posts: 5,883	Re: proper carb adjustment steps man if it was not for bad luck you would not have any luck at all... sounds like my luck as of late.. please don't take this personal. all info to follow is just my opinion... sounds like your still dealing with a leak at the intake runner or with the carb it self. or the spacers you got the carb mounted with. this is what makes the carb idle all over the place. with the spacers and this carb you got..o-boy me , i am done with holley carbs. nuf said.. your going to have to start with a process of elimination. starting at the intake runners..re-tighten again. make sure you got the gaskets installed correct. i would mount a correct carb..even a 2300 500 cfm holley carb would be better than the economaster carb. what ever it takes to get rid of the spacers. i am the nicest guy in the world. and am only trying to lead you in the right direction. and i have read some of your other post and see your pulling your hair out here, trying to get this bad boy running correctly. the problems you have right now..are more than a adjustment on the carb. this i can say with 100% confidence. your pal mark

06-03-2006, 02:56 AM	#3
Karl Hoh A little east of nowhere Join Date: Feb 2006 Location: LaBroquerie,Manitoba Canada Posts: 168	Re: proper carb adjustment steps Man, I though you beat this thing. I agree with RageNRat, go over everything with wd-40 or carb cleaner to find the vacuum leak/leaks. It has to be able to idle controllably ( is that a word?) @ 600-800 rpm. If you get it, post, I'll explain how to set it. ( it's been a looong day & I'm too tired to type that much now.) Good luck. Karl __________________ 68 C10 250 4spd 69 C20 327 4spd 69 910 250 3spd 80 K10 350 4spd 76 C60 366 5spd school bus "THERE'S NOTHING YOU CAN BREAK THAT SOMEONE CAN'T BE PAID TO REPAIR" Last edited by Karl Hoh; 06-03-2006 at 02:57 AM.

06-03-2006, 06:13 AM	#4
zeeklu Registered User Join Date: Dec 1999 Location: Northwest NJ Posts: 746	Re: proper carb adjustment steps http://www.bob2000.com/carb.htm Chris



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