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Feb 9, 2007 | 05:00 PM

Redneck1465

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Choke

I have a 85 F150 with a 351W 4bb Holley on it. This is the stock carb that came with the truck. I am wondering if there is something wrong with the choke becuase the truck seems to idle really high while in park after i first start it. And the idle will not go down. Its almost like the trucks running constantly on fast idle and I cant get it to kick down. Any suggestions would be really appreciated.

Feb 9, 2007 | 05:27 PM

ken's 80

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From: Milltown, NJ

Redneck,

Did you just get the truck? Is the idle problem something new?

Have you checked your "fast idle adjustment screw"? Also check the "step down" linkage to make sure it's not jammed.
Maybe a little WD40 in there?

I know these questions seem "simple" but with only the info given I thought I would start with the basics.

Feb 9, 2007 | 08:05 PM

Redneck1465

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I have had the truck for a little while now. When I first got the truck it had sat for 8 years in my buddys yard so it didnt run at all. It has only started to do the fast idle with the current cold wether we are having. I rebuilt the Carb rebuilt the motor. The step down linkage is the bar that runs from the trans to the carb right?? If so that is not jammed either. Is the fast idle adjustmant on the front of the carb??

Feb 9, 2007 | 09:59 PM

Franklin2

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From: Virginia

The fast idle adjustment is on the passenger side of the carb. It's directly related to how much the choke is shut.

The first thing you need to do is on a cold morning, start it up with the air cleaner off. Observe the choke door in the top of the carb. It should be completely shut after you press the gas to the floor, before you start the truck. Then after you start it, it should crack open a little bit, and be on fast idle. Run it a few minutes at fast idle, and then kick the gas pedal. The choke door should open a little more, and the idle should drop a little bit. If the choke door doesn't open, you can adjust the round black thing on the side of the carb to "leaner" and it should open some.

It may take a couple of mornings to get it set right. If you get carried away and set it too lean, then the engine may be finicky and want to stall till it warms up.

Feb 9, 2007 | 10:19 PM

Redneck1465

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Thanks. When I kick the gas pedal the idle wont drop at all. I need to adjust the round black thing then?? Does it matter if this is an electric choke and not a manual choke?? Which way is leaner on the adjustment??

Feb 10, 2007 | 12:12 PM

81-F-150-Explorer

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From: Northern California

Quote:

Originally Posted by Redneck1465

Thanks. When I kick the gas pedal the idle wont drop at all. I need to adjust the round black thing then??

Not nessecerily...

It is possible that the spring in the choke housing is broke and allowing the choke to remain in a rich condition all the time. Make sure the choke is opened all the way vertical when the truck is warm. Make sure the choke plate can move freely and without resistance. Clean if it looks dirty with carb cleaner.

Quote:

Does it matter if this is an electric choke and not a manual choke??

Yes and no... Check the emissions control lable for choke adjustment proceedure. Follow what it says on the lable. If it says, "Not Adjustable" then you wont be able to turn the housing as the adjustment is pre set at the factory and there are tamper proof locking tabs to prevent adjustment.

Quote:

Which way is leaner on the adjustment??

Looking at the back of the housing, usually left is richer, right is leaner. You can see the choke plate move while you adjust though. moving toward the closed position richer, open leaner, etc.. etc...

Feb 10, 2007 | 05:02 PM

ken's 80

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From: Milltown, NJ

One point redneck, (NOTE: I do NOT profess to be an expert here guys

) there are three screws that hold the choke spring housing (round black thing) tight. They must be loosened (just enough to allow the housing to turn) when you attempt to adjust choke plate.

If you loosen them completely the choke plate MAY move as you retighten them.

OK, TWO points:

Also do NOT close the chokeplate too far. Close it until you start to feel some resistance as you turn the housing. The plate should just rest against the carb throat closed.

OK, THREE ponts:

The stepdown linkage does not go to the tranny. It is connected to the throttle linkage which is connected to the accelorator cable. When you first start it cold, press the pedal and the cold choke spring should close the plate. As it warms the spring will expand and as it does will gradually pull the plate open.

Submitted humbly. Good Luck.