New Carburetor-tried adjusting idle and will not start now

[jlabatch]

I just bought an '83 that came with a new carburetor on a 3A-C engine. The car ran fine, the only issue was the idle was high (3000 RPM) even at normal operating temperatures and the fuel economy was not the best.
I attempted to adjust the Idle Speed adjustment screw and that brought it down a little bit. I turned off the motor and adjusted it more. I tried to start the motor and it will not start now. I did not keep track of where the screw initially was and now have no idea where it should be to attempt to get it back to the original location. Is there a starting point that I can unscrew from to get to a start point?

I also manipulated the fast idle screw but that did not seem to have much of an affect on it.

I also adjusted the mixture adjustment screw, but I later put that back to its original location once the motor did not start.

Can I assume the motor was flooded or is there a specific set of steps I need to complete to get the motor to fire back up again?

Thanks for all of your help

[ARCHINSTL]

Welcome to the Club! Lots of helpful and savvy people here.
Where are you located?
Did you notice that there is a FSM available for download? Look for the DOWNLOAD... sitcky in both the General and Repair Guides Forums.
Tom M.

[jlabatch]

Well it started, I did notice the guides and I do have a manual as well of my own, but if anyone has any tips or anything feel free to let me know.
Thaks
Josh

[Petros]

welcome to the list!

There are a number of simple adjustments on the carb, but there are a lot of other issues that can cause it stall at idle. Like a vac leak. So you also have to verify that all the vac lines are connected to the correct locations, that there are no vac leaks, and that none of the equipment and vac operated emissions controls system are faulty and causing it to act like a vac leak. There is no amount of carb adjustment that will make up for a vac leak or misrouted vac lines. Also check your spark timing and set it at 10 deg BTDC (rather than the factory 5 deg).

There should be no reason to mess with the idle mixture, the only other adjustment is idle speed, and the adjustment on the other side of the carb from the throttle cable that slows the closing of the throttle. Once you have it idling in the correct rpm range than you can turn the idle mixuture screws in or out have a turn each to see if the idle will smoothout (you turn it inwards until it idles rough, and than outwards, and put it half way in the middle).

Good luck.

[jlabatch]

Would a lose thermostat cable affect bringing up my temperature reading and bringing down my fast idle speed to normal levels? It stays at 3000 whenever I drive it. My only other option would be that the thermostat is stuck open. The temp reading does not go past 1/3 on the gauge.

It runs fine, just wont come down from a fast idle.

[marlinh]

You need to confirm that the carb isn't stuck on the fast idle cam. That would prevent it from dropping down to idle rpm even after it is warmed up. There is a cam shaped lever that holds the idle speed up. You need to check if it is on the fast idle stop. The fsm should describe where this lever is. If it is sticky, a bit of penetrating oil and some manual movement back and forth should free it up.

[dlb]

what marlin said. confirm the fast idle is not sticking, play with different idle adjustments until you get it started, and then set both the idle and fast idle using the procedures in the FSM that tom mentioned.

you shouldn't need to adjust the idle mixture screw. did you remove the plug for it, or did the PO do that? i've never seen one removed yet, or even had to do it myself.

[jlabatch]

I will look into some of these things tomorrow. You guys rock.

[Petros]

The temp sensor on the choke that controls the fast idle is self contained and independent of the engine thermostat, no the temp sender wire will not make a difference.

Also remember to check your throttle cable adjustment, if there is no slack it will not idle down. check for vac leaks on the intake manifold where it meets the head, or for the rare occasional crack in the manifold (this happens when the lower support bracket is left off by a mechanic when servicing the head/intake/exhaust manifold).

[splatterdog]

Another thing to consider is the idle cut solenoid. If it isn't working, someone may have raised the idle so it will run.

[keith]

Your high idle could be due to a defective choke pull off, that would hold the fast idle cam on all the time. step one has to be to ensure that the throttle stop screw is not stuck on the fast idle cam.

The next thing I would suspect is the throttle plate screws. You say it is a new carburetor but I'm sure you mean that it is a rebuilt or remanufactured carburetor. There is a little play on the throttle shaft and if the plates are not completely centered when the screws are tightened down, the throttle will never completely close.

The old trick for a flooded engine is to hold the pedal to the floor for 30 seconds, then, while still holding the pedal down, turn the key to the start position. This will usually clear the flood and the engine will start within a few seconds. Let up on the gas pedal when the engine starts of course.

[dlb]

The old trick for a flooded engine is to hold the pedal to the floor for 30 seconds, then, while still holding the pedal down, turn the key to the start position. This will usually clear the flood and the engine will start within a few seconds. Let up on the gas pedal when the engine starts of course.

keith, how does this work? wouldn't it just make it flood more? we bought an '87 ford camper van that is hard to start when cold so i might try this next time but want to understand why it works.

[Highlander]

David- by not pumping the accelerator you allow the excess gas to be pumped out of the combustion chamber. You are also holding the throttle plates wide open which decreases the resistance to air flowing into the intake manifold.
If its an Injected unit, refrain from cycling the ignition on and off as well, the injection will give a spurt of gas when you cycle the ignition power to increase the amount of fuel (choke it) for a cold start.
If its not flooded to start with, holding the pedal to the floor won't help it to start unless the choke is set way too tight. You can check this by inserting a screwdriver down the throat of the carb, before attempting to start it cold, to hold the choke plate open, then try to start it, if it starts easily then the choke is too tight.

[jlabatch]

The temp sensor on the choke that controls the fast idle is self contained and independent of the engine thermostat, no the temp sender wire will not make a difference.

Also remember to check your throttle cable adjustment, if there is no slack it will not idle down. check for vac leaks on the intake manifold where it meets the head, or for the rare occasional crack in the manifold (this happens when the lower support bracket is left off by a mechanic when servicing the head/intake/exhaust manifold).

Throttle cable was taught, ding ding ding
That slowed it down to about 1200 RPM but still not the suggested 650. And this was at normal operating temperature. I need to play with the idle speed adjustment a lil more to see if I can get it down further. Working in the dark is not fun. I am going to check all the vac lines next, but I adjusted the idle speed adjustment and that smoothed out the sputter in the idle it had a lil. I imagine the vac lines will be the last thing to clear any final sputtering.

The fast idle cam, from what I can tell, is not stuck. It slid over when I moved the throttle while holding down the rest of the components.
The throttle plate screws could be an option.

[Petros]

I have never been able to get one to idle reliably at 650 rpm, it might be due to the fact that most of the cars, including mine, have many many miles on them. likely there are small internal leaks from wear and age. I usually idle them about 800 rpm which seems to prevent stalling and stumble. So you are not far off now.