Hard Starting after sitting overnight

[kna4977]

Quadrajet equipped 350 hard to start after sitting even just overnight. I have to pump it several times and once it cranks it’s like it’s flooded smoking and doesn’t run on all cylinders until everything clears out. Any ideas what might be going on to cause this?

[geezer#99]

Choke working?
Which style choke?
Pics help.

[kna4977]

Originally Posted by geezer#99

Choke working?
Which style choke?
Pics help.

Seems to be but I need to take a look. Thinking possible well plugs leaking down??

[Willshook]

Q-jets end up leaking at the bowl seals when they get this old, which can dump fuel in the manifold. Easy fix with kits or just some epoxy if you want a quick and dirty fix.

Dunno if that's the issue but worth looking at given the symptoms.

[geezer#99]

That’s a divorced choke.
When the motor is stone cold crack open the throttle and if the choke is working correctly the choke plate should close completely.
Check that and report back.

[kna4977]

Originally Posted by geezer#99

That’s a divorced choke.
When the motor is stone cold crack open the throttle and if the choke is working correctly the choke plate should close completely.
Check that and report back.

I see a good stream of fuel from the accelerator pump. Did 3 or 4 times and same amount. The choke doesn’t close fully at least the times
I tried it. Has 3 steps. I was able to close it manually. Some times lately it would seem to stay on higher idle even when warm and I would really have to kick the throttle some times more than once to get it to drop down.

[Dead Parrot]

2nd the bowl seal issue.
Also your float could be leaking(brass) or fuel logged(composite) causing a high fuel level.
A fuel pump with a slow leak can also cause the carb to lose fuel overnight.

Get that timing set first. Less then optimal timing can contribute to a cold start issue.

In addition to things already suggested, as a test, use a screwdriver to prop the choke flap open, then try to start. You might need less choke then the current adjustment.

[geezer#99]

Good stream of fuel tells you the bowl isn’t draining.
Here’s a thread on getting the choke to work right.
Just a linkage rod adjustment.


https://67-72chevytrucks.com/vboard/...d.php?t=728197

[Dead Parrot]

Make sure that vacuum pot is working. If it is stuck, it can cause choke problems.

[kna4977]

Have the initial choke working where you hit the throttle and the flapper closes fully then it cranks cold fine. Once it cranks initially the flapper stays closed vs opening and it floods and smokes. I opened it manually and it ran well. Cranks warm fine.

[geezer#99]

Choke pull off is likely toast.

[kna4977]

Originally Posted by geezer#99

Choke pull off is likely toast.

Choke pull off holds vacuum and works like it should. The choke closes no problem for cold start now, but stays in that position unless you open it up manually. So although the pull off is working like it should, the other piece with different steps (not sure exactly what it’s called) sticks closed.

[geezer#99]

Post another pic that shows the choke linkage better.

[kna4977]

Originally Posted by geezer#99

Post another pic that shows the choke linkage better.

Here’s two pics one with vacuum applied to the choke pull off and one without. Notice how the rod that’s supposed to open the choke when vacuum is applied to the pull off doesn’t change positions and the choke pull off is in as far as it can go. This rod needs to be shorter to do its job I imagine. I’ll attempt to bend the rod where the choke blade opens about 1/4” with vacuum applied to the choke pull off.

[cadillac_al]

That's how you adjust them, by bending the rod. I like that air cleaner spacer, it makes it easier to work on the choke. Where do you get that?

[kna4977]

Originally Posted by cadillac_al

That's how you adjust them, by bending the rod. I like that air cleaner spacer, it makes it easier to work on the choke. Where do you get that?

Air cleaner spacer is factory.

[Orange Crate]

Good info here for Rochesters

https://vetteworks.tripod.com/qjet.htm