No choke?

[Monteman87]

Hello all, scratching my head and have no idea where to start. 87 305 with the Rochester Quadrajet, inherited the car from my dad, and is now my project.. Choke will not work, best I can tell..my trick now is to turn the A/C on(which isnt charged) at start up, which holds the RPMS at 1800 ?, once it gets up the operating tempature, I turn it off and it idles fine.. or constantly start and restart while I hold the throttle pedal down slightly again til it reaches operating tempature again. Ive attached some pictures, just looking where to start.. EGR valve has been deleted it appears, and there are a couple wires with green and yellow connectors, not plugged in.. Thanks.

 

[85442/86buick]

hello ,
really need a large image of the passenger side ( choke side ) is it plugged in ? and did you add or change the electric choke ?
and if plugged in , where is it pulling power from ? is it tapped into some other circuit or the fuse panel directly ?

and what is that brass tee doing on that vacuum line ? doesn't look factory.

and if your keeping the CCC system replace the EGR !

my 2 cents

 

[Bonnewagon]

Looks like it is wired in. The choke is pretty basic. On a cold engine, not running, when you press the gas and open the throttle, the choke flap should close completely. If not, loosen the 3 screws, turn the black cover, and adjust so it does. This also sets the fast idle speed. Once the engine starts, the vacuum break on the side behind the choke should open the choke flap slightly so it won't stall. Then the electric choke gets hot, and slowly opens the flap all the way. Check for 12 volts at the choke wire in 'RUN'.

 

[Monteman87]

hello ,
really need a large image of the passenger side ( choke side ) is it plugged in ? and did you add or change the electric choke ?
and if plugged in , where is it pulling power from ? is it tapped into some other circuit or the fuse panel directly ?

and what is that brass tee doing on that vacuum line ? doesn't look factory.

and if your keeping the CCC system replace the EGR !

my 2 cents View attachment 236605

Basically a rebuilt carb for National Carb, here in town. For starters, not knowing any better I assumed that was the problem, so I swapped it out. I know, I know assume.. I get it.. Its plugged in, vaccum line runs to dash gauge..

 

[Monteman87]

Looks like it is wired in. The choke is pretty basic. On a cold engine, not running, when you press the gas and open the throttle, the choke flap should close completely. If not, loosen the 3 screws, turn the black cover, and adjust so it does. This also sets the fast idle speed. Once the engine starts, the vacuum break on the side behind the choke should open the choke flap slightly so it won't stall. Then the electric choke gets hot, and slowly opens the flap all the way. Check for 12 volts at the choke wire in 'RUN'.

Adjust the choke flap while at WOT correct?

 

[Bonnewagon]

NO! When you press the gas pedal, cold, the flap should close totally. And remain closed until the engine starts.

 

[spongbob]

It seems generally tru that on some older carbs you can just set the choke untill it's 1/8" from being closed ( helpful ?)if the above mentioned methods seem questionable .again the cold weather foot pedaling

 

[69hurstolds]

Technically, the choke flap opening with the front vacuum break is set with an angle gage. But yeah, when cold, set the choke by one press of the accelerator pedal or hand blip of the throttle. Choke should snap closed. If not, adjust choke housing by loosening the screws slightly and turning the black housing counter clockwise to close the choke flap. You don't want to over do it, just as long as the choke goes all the way closed when cold. Then apply vacuum to the front vacuum break pod and keep it all the way pulled in. The choke flap should open slightly, which if you take an 1/8" drill bit as a gage to set the opening, you can use the screw on top of the vacuum break to adjust the opening (still having vacuum to the vacuum break applied) and that should get you close. When done, hook up the vacuum hose back to the vacuum break, start car as normal and observe the choke and ensure it opens. If it stumbles and stalls and loads up, then adjust the choke flap to open with the vacuum break just a hair more. You don't want it to open too much or you're back where you started.

If you have to adjust the fast idle speed, it is set by a screw down by the primary shaft. That's a bit of a different procedure.

 

[Bonnewagon]

The vacuum break is critical because once the engine starts, it needs more air to run. Since hardly anyone has the angle choke gauge, if you go back to where specs were before that, you will find an inch spec. Every carb was different. I have found that between 1/8" and 1/4" pretty much covers them all. The rule is, if the engine dies, too much air, so close the flap a bit. If it runs rough and lumpy, not enough air, open it a bit.

 

[stew86MCSS396]

Someone mentioned checking for volts at the connector, Key On Engine Off...the stock wiring on the '86 SS ran through an oil pressure switch...no oil pressure=no choke element heating. Check it with the engine running.

I'm no help with adjusting the choke. I seem to recall living with the problem on the '87 LS. I'd pop the air cleaner off and made sure I was getting at least a squirt from the accelerator pump then hold the choke flapper closed to set the fast idle cam. Starts on the first try every time and I would motor away on the fast idle cam. Idle would drop down after using the throttle once. Any subsequent 2nd start of the day was not an issue.