gtpro700

Hey guys, I have a 750 mighty demon and just got my motor going. I have been having a problem when I rev the motor it doesnt want to always come back down to idle. I know its not the cable because I am physically pushing the linkage back to idel position and it is staying up. Unless it is binding or stickign on the opposite side of the linkage (secondary side) then I am not sure what is goign on. I have left the out of the box settings thus far and am not sure what to mess with seeing I used to be a fuel injection guy and am now gettign into carbs. I have heard a lot of people say that out of the box they have ran these carbs and they were great as is. Just my luck to have a problem with it lol Any help would be appreciated as to what might be going on. Thanks!

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gtpro700

bump

1A Dan

probably a dumb question, but gotta ask anyway: did you hook up the return springs to it?

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1987 Trans Am, work in progress
2008 Pontiac G8
Retired: 1984 Camaro "ZF" 2.8L, 1989 Camaro RS
Customer Service Manager, 1A Auto Parts

EvilCartman

Another thing a friend ran into with not returning to a low idle all the time... too light of a spring in the distributor. It was right at the rpm where the weights started to fling out. Try adjusting the secondary side idle screw to bring the idle down a bit and give it a few revs to see if it returns properly.

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gtpro700

1a dan I know you had to ask but yes I do have the return springs on lol Even if I didnt when I rev the carb by hand and brign it back to idle position it doesnt come back down from the rev.
Evilcartman why would the light springs in the distributor effect if it would come back down from a rev or not ? Thanks for the help guys.

Badass355ciz28

ive actually ran into that problem with the springs in the dist being to light since demon carbs like 16-20* initial timing......... try a stiffer spring setup and a lil stiffer return spring. should be a double spring return

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EvilCartman

The lighter spring lets the mechanical advance start at a lower RPM right? Now if it's at the border line rpm of not being able to bring those weights back in where you have your idle set, then it's going to keep that little bit of advanced timing. That timing advance will keep the engine speed up even though you've let off the throttle. Chased it for about an hour on a friend's car changing springs out but finally ended up just locking the distributor out and all was fine. He has a big solid roller though. Another thing to check for is vacuum leaks just to make sure.