So I fixed an unplugged port on a PVC valve behind my egr which has been giving me problems. But when I was leaning over I noticed where the Carb sits on the manifold by the throttle linkage (drivers side) and by the choke assist on the passenger side is leaking some fluid. I haven't checked to see if the bolts are loose yet. But gasket replace? Or Carb rebuild? All I know is it shouldn't be moist there.


I am having problems with my choke as well. Is the plate supposed to move freely and easily? My truck no longer has high idle or anything. So I know I'm going to need to set the choke properly and replace the choke thermostat and probably the pull off.

The Carb is a motocraft 2150. Time for a rebuild or repair? It seems to idle fine when warm, no hesitation or anything. But before I'm at operating temp the truck (I let it warm up usually 5 or so min before I take off) hesitates and chugs when accelerating until I get to about 20mph. I'm assuming that's choke related though. The biggest thing is uphill the truck doesn't seem to be able to carry itself. Foots in the pedal and I can't really get it above 55mph up hills if I'm doing 65+ then hit a hill it'll just act like my foots not even in It and drop to 55. Any ideas?.

Sorry if its hard to read. I'm posting from my phone at work.

Sounds like the bushings on the throtle shaft are worn and letting fuel leak on both ends. Those same leaks can also be a slight vacuum leak. I have never seen these come in a rebuild kit. Sounds like a replacement is in order unless you have a rebuilder nearby that can replace the bushings. I believe that it takes some machining to do it.
The choke should move freely also. If there is any binding, it can't work properly.

Hi, I would start by replacing both gaskets. Then you need to adjust your carb. There's the choke, the air/fuel mixture, idle and don't forget to reset timing. All play a part in a carbed engine to make it run smoothly and efficiently. You didn't mention any studdering or hard starting, so I'd say the float is good in the bowl. You can see if the choke is working by observing it in the morning when the engine is cold. Should only take a minute to see the plate start to move. Hope this helps, I can give you more information since I've just gone through this myself, but I'm on my iPhone. Have to wait till I get home, sorry.

sgarver said:

Sounds like the bushings on the throtle shaft are worn and letting fuel leak on both ends.

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How can I check the bushings? I've heard that you can move it a certain way to check if its worn out or not. I'll search some on it.

Amkatt1, I'll check the coke operation in the morning. It'll be too late when I'm home. I don't think I said it too well earlier but the truck does chug in cold idle until it warms up sometimes ,rarely but sometimes it does die if it isn't warmed up enough on cold starts. I do one to two good solid pumps on cold starts.

Here's more info. Buy a can of carb cleaner to spray around the base and throttle shaft area of the carb. If there's a vacuum leak or worn bushing, the idle will jump. What I meant about the float is that if it was saturated and sitting low in the bowl, you would experience flooding, hard starting, and bogging out when taking turns,etc. To adjust the carb, you will need a vacuum gauge. You will also need a timing light. Start by gently turning the air/fuel screws till they seat. Then as a bench mark, turn each one out 3 turns. Then use the vacuum gauge to get the highest reading. You will now need to re-adjust the timing. After the timing, re-check vacuum. Will take a few times, but once your happy you can set the idle screw. The choke has two areas of concern. Is it set properly when cold. The choke plate should be open just about the thickness of a paper clip. Next, the set screw for the dog on the choke linkage has to line up with the "V" indentation. This has to be done when cold. It's hard to see, but I used a small mirror. Now when hot, the choke plate should be fully open. The black dial on the side will adjust for lean/rich. If someone has turned it to far either way, the plate will not operate properly, and it may be jammed or broken. Easy to check, take cover off. With a little patience, you will get your truck running smoothly. Use the rest of the carb cleaner to clean inside the throat. Hope this solves the issues your having.

I will take a look at it this Thursday on my day off and let you know. Thanks for the step by step. I am pretty sure the dial isn't set properly so I will double check that. Thanks man!

If the leakage is above the base of the carburetor, and it is leaking out both sides, it probably is the throttle shaft.

If your issue is only on a cold start(sounds like more than that) where the engine starts just fine, then idles high and dies, the problem is the choke pulldown diaphragm. The diaphragm is pulling the choke open too far.

fatherdoug said:

If the leakage is above the base of the carburetor, and it is leaking out both sides, it probably is the throttle shaft.

If your issue is only on a cold start(sounds like more than that) where the engine starts just fine, then idles high and dies, the problem is the choke pulldown diaphragm. The diaphragm is pulling the choke open too far.

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Thanks fatherdoug!! totally forgot to add that one more item that concerns the choke. Small adjusting nut on back of the diaphram. Turn in for less pull, turn out for more. Sometimes I would rather have EFI

No, Thank You! I couldn't remember which direction was which on the adjustment screw. . A well built carburetor(with all its pitfalls) can often rival an EFI unit. I like turning heads when it's -25 and the truck starts right up - with a block heater of course.

Thanks both of you! I got the choke adjusted properly. No more stuttering when cold on take offs. I have my idle set right.

Only two things I have to figure out is:
1. I don't have high idle so when cold I turn the truck on and the rpms are low at like maybe 400ish until it begins to warm up then it goes into regular idle which is about 650/700. Could this be choke setting still or just high idle setting?. I didn't have enough time to mess with that this morning.

2. Again idk if its choke or carb still needs to be adjusted more but when I'm taking steep hills the truck doesn't seem to have the power to maintain 65. It'll drop to 55 and if I put my foot in it. It will drop to 2nd and gain a bit of momentum. I just recall being able to take hills easier. My foot will be in the pedal but it feels like it doesn't matter unless its almost on the ground. Any ideas? Carb needs to be adjusted more? Or throttle bearings? I sprayed some Carb cleaner around the Carb and the engine didn't rev up at all.

Thanks guys! Carburetors are a foreign language to me. I can rebuild transmissions and tune them all day long lol

Check to see if the choke plate is all the way open, as in completely vertical. It sounds like your still getting some choke action when the choke is supposed to be open. Of course you will have to check it when the engine is up to operating temp.

If your engine rpm is only 400 at cold, then you still may need some adjustment on the pulldown diaphragm. Like Roy(amkatt) said, there should be the width of a paperclip between the choke shaft and the carb body after starting the engine when cold.

That's awesome! It's your high idle cam (I called it a dog earlier) It's a PITA to get exactly right.The set screw you turn for adjustments has to be right on that little "V" indentation for the idle to work and kick down properly. Remember the engine has to be cold for this. You will have to manually snap the throttle plates and see where the cam comes to, will take several times.

Thanks fatherdoug. I will take a look at it and see what I can do.

Ahhh, I have to type faster, did you see my post?

The fast idle cam works with the choke. It's purpose is to have the throttle plate open slightly to allow higher idle when cold and as the engine warms up and the choke plate moves, the cam steps down and will completely disengage when operating temperature is reached.

amkatt1 said:

The fast idle cam works with the choke. It's purpose is to have the throttle plate open slightly to allow higher idle when cold and as the engine warms up and the choke plate moves, the cam steps down and will completely disengage when operating temperature is reached.

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I wish mine would do that!

fatherdoug said:

I wish mine would do that!

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you can keep your foot on the gas pedal for 5 minutes. does the same thing

amkatt1 said:

you can keep your foot on the gas pedal for 5 minutes. does the same thing

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Mine doesn't come OFF of high idle until I bump the throttle.

fatherdoug said:

Mine doesn't come OFF of high idle until I bump the throttle.

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Oh, that's different, that is the better of the two. you can leave the truck to scrap the windows

amkatt1 said:

Oh, that's different, that is the better of the two. you can leave the truck to scrap the windows

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Haha. Well I am used to keeping my foot resting on it. Been doing it for years when I lived in East Washington winters!

The high idle I will tinker with. I just want to make sure I get everything tuned and adjusted right so no loss of power. I'm about to move back to Washington in a month or two and have a list of stuff I want done before I trek 1700 miles from San Diego. You guys have been awesome!!!