Rebuilt carb....not im having choke problems...

[Workin' Rig]

Ok, i finally got around to rebuilding my carb....truck runs SOOO much better, more power, idles better, almost perfect throttle responce....BUT....

Before i rebuilt it the choke worked perfectly...it had high idle and started wonderful on cold mornings...

Now, i belive the choke is closing but i have no high idle, or very little, and, its alot harder to start and get going....

I did not mess with the choke one bit when i rebuilt it besides setting it a little richer cause its gettin colder out.

Would the choke pulloff have anything to do with this? Im wondering if igot it hooked ot the wrong vaccum port?? I have it hooked to the big one on the back of the carb...

any ideas would be appreciated.

 

[fatherdoug]

Did you replace the choke pulldown diaphragm when you rebuilt the carburetor? If you did, and everything was replaced as it was before, the diaphragm will need some adjustment.

Just went out and looked at mine. The vacuum line for the pulldown goes to a smaller line right next to the pulldown diaphragm. The larger vacuum source goes to the PCV valve on mine.

 

[Workin' Rig]

Nope, i didnt all i did was unhook the vaccum hose to get the cover off the carb.

 

[Truckin4life]

From your Original post and doug's reply it sounds like you have the vac line hooked up to the wrong port...

Which would explain why the choke aint working.

Post up once you get it figured out....

 

[Beach66Bum]

that vacuum line that feeds the choke pull-off is attached to the carb itself,
(that's the 2150 Motorcraft carb on mine)

This picture is a cold start-up, it shows that the choke plate is about 1/4" open when the engine first fires up. The choke plate must open this amount to prevent stalling. There is a cam that has an adjustment for the high idle etc. There is a "V" indentation on the cam that you use as a reference to set the proper high idle when cold. I will get a better picture for you of the old carb.

 

[BuzzGun79]

The pull off needs a constant source of vacuum Workin usually a port on the rear of the carb will provide this.

 

[fatherdoug]

Thanks for the picture, Roy. I implied that the vacuum line attached to the carburetor, but I didn't state it outright. Mine goes to the same place yours does.

 

[Beach66Bum]

Your welcome Doug

 

[Workin' Rig]

THat picture helped because thats where i got my vac line hooked to.

If you could i would like the high idle pic....I think thats my issue because the idle seems to get higher as the engine warms up (just into the normal band) then i blip the throttle and it comes down, but as soon as i give it throttle it high idles again (not as high as it does on "high idle" but higher then normal idle).

What confuses me is i didnt screw with any of that.

 

[m78]

There's supposed to be a little aluminum tube that transfers heat from the manifold to the bottom of the choke dial. If its clogged or missing the choke won't release properly. I think it's natural for the rpm's to increase a little as it runs a while on choke, and you have to bump the gas to release it.

 

[Workin' Rig]

THere no aluminum tube or even a place for one...i know what your talking about my 83 F150 had one on its 300 I6...never seen one on a V8 though..

There is a place for the preheater "duct" to go up to the air cleaner...and thats missing....

 

[Beach66Bum]

Morning,
not all chokes rely just on the hot air to operate,
Ford has three set-ups for choke operation,
1- full electric
2-electric with hot air tube
3-hot air tube only

all three systems work fine, just takes a little longer to get to normal idle with only the hot air. You can see that mine has both.

the fast idle cam has three steps,
first will be your high idle, usually 1500rpm,
when you tap your gas pedal, it will step down to the second position on the cam, thus lowering the rpm to about 1000 rpm (give or take) when it is fully warmed up, the cam is COMPLETELY disengaged,

the adjustment screw for the cam must not be touching, I will post the picture later today, much easier to see with carb off,

 

[Workin' Rig]

Ok thank you i appreciate it.

 

[Beach66Bum]

OK, a few pic's of an old 2150 carb

showing the cam and set screw for high idle adjustment

hot air tube connector

vacuum hook-up for choke pull-off (constant vacuum applied)

 

[Workin' Rig]

Aweome thanks!