carb problems
 

found out my secondaries are not opening what so ever...played with vacuums ...nothing seems to work?..any ideas and/or pictures of vacuum li9ne set up would be awesome!

it is an 84 gmc pick up 305.L..rochestor

Re: carb problems
 

Are you sure they are not opening? They will only open while driving. The lower plates open mechanically due to linkage and the upper plates open slowley due to the vaccum created when the lower plates open. The upper plates open up and lift the secondary metering rods thus creating the flow of fuel. With the engine off, you should be able to push them open with your finger, once open, reach over and manually open the throttle and look down the bore, you should see the lower plates open....
Only thing that could keep them from opening is either binding up or the secondary vaccum break on the pass. side of the carb....

I'll see if I have a schematic laying around....

Re: carb problems
 

when idleing...hood up...i will hit the throttle and secondaries dont open. upper sec were sticky so i freed them up. this carb only has the rear choke pull off. and im confident that the vacuum line hooks into the back of the carb. which is full time vacuum...but holds the choke pull off and keeps the upper secondaries from opening....i will have photos of my setup for tommorow..too dark now....now with messing with this i believe i have done something to my vacuum advance to the dist..i now have a knock

Re: carb problems
 

The secondaries won't open with the vehicle sitting in neutral or park and actuating the throttle. The engine needs to be placed under load.

Or at least that is the way they are designed to work.

Re: carb problems
 

I usally bend the little tab on the side so they always go.....

Re: carb problems
 

lol

Re: carb problems
 

decoded the carb...1984 4 BBL cadillac. this is the original carb for my truck.

have some pictures here..obviously i gutted emmissions.

Re: carb problems
 

:gmc2:

Re: carb problems
 

:chevy:

Re: carb problems
 

i hooked up the vacuum advance like it was before and i now have a knock.

Re: carb problems
 

better yet..who here with a 305L removed all of the emissions to the carb....if you have then how is your hook up?