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1985 720 Throttle stuck wide open


1985 4x4

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Ok hopefully I can get some help here, 85 stock truck the carb is stuck wide open, this is my daily driver. As soon as it starts it stays open and will not go back. It starts and immediately revs to red line. 

 

The throttle cable is new

white grease applied to the pivot where the cable goes.

 

Any help would be greatly appreciated.

 

I have no way to get to work tomorrow I will check on the half hour for responses.

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it was happened on the way home when driving went to the rev peek so I shut her off, tried to fix on the roadside no luck towed it home with a friend, the next morning manually it worked fine I had a zip tie on the inside pulling at first and was able to throttle it,  then when I went to start it.... it stuck at the full throttle position again but permanently  it seemed when it went to the high rev on the way home something released or snapped.  I can send a pic from my phone or what ever is needed to see if something is not right

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So the throttle actuates properly when the truck is off? What happens when you move the throttle with the truck running? Is it jammed?

 

Is the throttle cable new since this happened or did you replace the cable recently and then this happened?

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Also, 720 threads are frequented less than many others. You might have better luck closing this thread and starting one in general discussion. Most of the guys online at night surf there a lot.

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ok here is the pic, is there a spring that is supposed to go to hole #3 to the pin that has the ? by it, also looks like a cir clip groove. there is a second hole with the lever behind it as well. 

Home all day I need to resolve this asap. I hope to fix her before the wife gets more pissy....   thanks   I can also message you my cell # might be easier

 

720carb_zpsghfpbe2r.png

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Can you draw back and picture the whole carb?

 

How many butterflies hold the air filter on? If two then you have a Z24i with throttle body injection. I should have looked at your location.... California. You almost certainly have the fuel injection engine.

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mike isnt that a idle shutoff selinoid on there.

 

if you shut it off when its wide open then open the airfilter and look inside the carb and see if the plate is stuk open.

 

 

cables should have a nice slow bend to them so the cable can slide ez inside the cable case. to many bends then it binds up.

 

if cable good disconnect the cable then manual operate by hand and see if it binds up then

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expanded view electro injection

 

manually it pivots fine, manually does not override the high rev, something else is causing it to stick I took off the cable then started it..... and it acted like the pedal was through the floor max rev limits for sure.

 

20151011_224817_zpsczzyctvf.jpg

 

20151012_114247_resized_zps6klyfltn.jpgI

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Looks like the cable is too tight, remove it and have a go.

Driving this home on Friday eve, the idle revved once and I pump the pedal a few times, and it went back to normal operating conditions,,,,5 miles later it seemed like something let go or snapped. The engine went to full throttle so I pushed the clutch in and turned the key off ...was unable to change this from this point, I checked the cable operation which seemed just fine but loose, I went ahead and changed the cable thinking maybe it was fraid or something inside or it had stretched out, I looked to see asap if a return spring at broke or something but there was no residuals of parts. I know in the past with other cars if the spring snaps there is something left on the ends,,,,there was nothing.  

 

the carb goes to full throttle open with the cable completely disconnected.

The pivot area where the cable bridges over and connect at the end rotates fine with plenty of recoil.

if a spring broke or is missing I dont know where it would even go, I have a photo asking about three items one being a hole which looks like for a spring end and then a small stud that sticks out with nothing on it. (pictured above,

 

I have no idea and wish I knew more about this and I am looking for options

 

message me direct and I can give you my cell #

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Does the lever that looks like it has a small stud move when you unhook the cable and manually move the throttle linkage? Does it move at all? With the cable unhooked can you pull up on the piece that looks like a stud without moving the part of the linkage that the cable goes over??

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Driving this home on Friday eve, the idle revved once and I pump the pedal a few times, and it went back to normal operating conditions,,,,5 miles later it seemed like something let go or snapped. 

 

Did you check the spring behind the throttle trunnion.........?........

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ok it does move up but not by hand which would rotate the pivot arm forward, then I could adjust the cable threads back. Are their springs available for this carb to put back on and second the spring would keep the stud  higher which I think would keep the throttle reversed back to stock position.

 

Anyone have a California set up like this to show me how it should go, anyone have a carb they took off that is for parts etc. so I can see how to install it. I do have a little more insight now and it does make sense.

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