[1980Impala]

I have put the 1850-3 holley 600cfm carb on my 350 chevy engine and it is having problems idling. I am having trouble adjusting it because I am not sure where to start. I traded it from a friend that said he put a weiland pressure plate on it??? Not sure what that does. Does anyone know how to adjust it or what the pressure plate does?? My enging won't idle and when i give it a little gas it stalls. I am not sure if anything has been changed in the carb. Thanks.

[1BAD80]

Here is Holly's site with free down-loadable manual and troubleshooters guide.

http://www.holley.com/HiOctn/TechSer...o/FMCTech.html

[engineczar]

wow I just finished rebuilding that exact model number for a customer.
I guess the place to start is to ask how long has the carb been sitting? If it's any length of time at all the gas will gel up, get gummy and all the adjusting in the world won't clear out the air bleeds and all the other passages where the gas needs to pass through correctly.
The carb I just did only sat for about 18 months and needed a fresh rebuild. Runs perfect now.

[1980Impala]

For a 350, what specs. would you use, like jets and stuff?? Thanks.

[1980Impala]

I found out they weren't pressure plates, but they were power plates. Anyone know about those. built by weiand.. thanks

[Jared]

first thing i would do is tear it down and soak the main parts in carb cleaner. then put a new gasket set into it and check your float Level, flip the bowls over and the float should hang level with the top (bottom now) of the bowl. that should get you close. then i would adjust the squirters so they are squirting the second you touch the throttle. make sure theres no delay or it will stall or backfire. if it back fires you have to replace the power valve usually unless its a 94 (or so) or newer. check your idle screws if its not idleing im guessing you need to back them out more. is this engine stock? if not you may need bigger jets. check the number on the primary side. the plate if im understanding correctly is your secondary jetting. theres a number on that too. make sure and write down both primary and secondary numbers. jet sizes will vary largely with your engine. try what you have and see how it feels and check the plugs. if the jets have 3 numbers on them like 641 then its the lean side of 64, 642 mid 64, 643 rich 64.