thinice

So after having my carbie rebuilt- My car doesn't seem to want to idle ... at all.
When I rebuild the carbie I didn't change/move _any_ screws for mixture/idle/fast idle.

Here's the problem:
When I start it up, it will idle on fast idle but when you pump the acell and take it off fast idle it will just die out- maybe run for half a second then you can feel it dying- puttering out so to speak. (it's not an adrupt stop is what I'm sying);

Can mixture be affected _that_ darmatically after a rebuild and not messing with the settings?

I'm just trying to get a good list, because when I get a chance to spend some actual _time_ on it I want to have any other ideas besides 'mixture' settings and choke settings.

The choke is supposed to be set 3 rich from index according to the engine decal (in which it is); Carb is a Motorcraft 2150 (D6AE-HA) on a 400 ('351m' block).

Tx in advance.

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76' LTD Landau (400)

brenx

Idle mixture can affect that.

Brenden

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XB Fairmont (street car) 11.07@123.02mph.

kionga

Hello Thinice.
It may well be that the idle/mixture screws were out of whack before rebuilding the carby. You need to adjust both idle and mixture screws at the time of fitting the carby. There could also be a blocked idle jet. Or an air leak-although you might hear that.
Do you have a tachometer? It will help when setting fast idle, idle and mixtures.
Cheers
Craig

old falcon fan

maybe a slight vacume leak somewhere too.....

thinice

Here's the culprit after much work with my old' man tonight:

A. The mixture screws were like... WAYYYYYYYY rich!!
B. The Positive closure spring around the choke-pulldown's arm was MIA.

This carb was clearly tuned for a 'limp' mode- which explains the crappy mpg - the horrible idle - and the horrible performance.

Gotta wait until tomorrow to get a spring to fit on there :(
But from what we've done so far- the idle is so much cleaner feeling - almost a 'finesse' feeling in the idle from what it sounded like before .

Next week is true duals!!!

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76' LTD Landau (400)

thinice

Also, the fast-idle adjustment screw couldnt even touch the tang on the linkage;

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76' LTD Landau (400)

TruBlu351

Good to see you've found the problem.

Somtimes people forget to fit the accelerator pump arm when refitting the fuel bowls, this can cause plenty of coughing when trying to accelerate, due no accel pump shot.

Make sure you're idle screws are turned out exactly the same amount on each side. If you turn one, then turn the other the same.

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XE Falcon
393 Tremec TKO 9"

thinice

little troubleshooting help now-

A. When the engine is hot-hot (lotsa revving with no movement) it'll diesel when you shut it off (I found this to be a seldom issue, out of about 20 starts-and-shutdowns it dieseled 3 times. (this could be due to load and frequency of starting and stopping of the engine)

B. When the engine is hot, (as hot as "a") it started to die on me - a quick tap of the accelerator and it idled fine. (this was only 1 instance out of the 20)

C. I have a unit that I can't idenitfy - maybe somone can help, it says something about servo arm adjustments- it's kinda like a big-black solenoid or diaphram almost, it's got a ball-chain linking it to my accelerator/throttle linkage. it's to the left above the master cyl - hard to miss really. any idears?

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76' LTD Landau (400)

TruBlu351

a: with a HOT engine shutdown, and therefore hotter combustion chambers, you could expect some dieseling. If your car has a good cooling system, you could let it idle cool down after a big rev session first. Also, your timing may be a few degrees too far advanced. BUT I wouldn't change it if the performance was good, just don't shut it down hot. If it doesn't do it after driving on the road (when cool) don't worry.

b: a hot engine transfers heat to the carby thru the manifold. This causes the fuel to boil, creating a "vapour lock", which results in fuel starvation. It's a weird one because you'll check the car over and 2 minutes later it'll work fine. You could have had a mild case, plus it was only 1/20. If it happened regularly, you could fit a heat insulating plastic/wooden spacer plate under the carb.

c: not sure on the black solenoid "thang". Pull it off and see if your car still works Is it on your carby or firewall? Not a vac sec diaphragm? or automatic choke?

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XE Falcon
393 Tremec TKO 9"

thinice

Thinking things over I'm guessing the mixture is a tad lean - perhaps a quarter turn richer will make the detonation a bit less hot.

This lucid 'black' unit is mounted on the top of the firewall - driver's side

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76' LTD Landau (400)