High Idle, sticky linkage...only while running.

[sirzepp]

I've done some search, but I can't find a problem quite like this. I will be taking it back to the tech who did the work on Monday, but I thought I'd try mud to see if I could diagnose it myself.

As the title says, the throttle linkage on my FJ60 is sticking and causing a high-idle. The carb was replaced(rebuilt) and the truck is running AWESOME now, but the linkage sticks at a high idle. I can tap the gas or put my foot under it and it will idle down. I can replicate the problem by applying a small force directly to the throttle linkage at the carb OR by gently pressing the gas pedal. I can then pull the linkage back to the idle stop by either directly manipulating it at the carb OR pulling out on the gas pedal. The linkage is smooth and free from the pedal all the way to the butterfly.

Here's the rub: It ONLY does this when the engine is running. I can turn the key OFF while it's "stuck" in this high idle and watch the gas pedal "pop out" about a 16th of an inch. When I start the truck, it's idling at the normal 650 RPM. When the engine is OFF, there is no resistance in ANY part of the linkage. When the engine is running, I can feel it stick, especially when I am messing with the linkage directly at the carb. All springs are present, and all linkage pieces are straight and connected properly.

Like I said, it's going back to the tech on Monday, but I'd like to see if it's a simple fix I can do myself.

 

[grant5127]

Check you A/C fast idle diaphragm for proper function.... back off the adjusting screw or disconnect the vac. hose and see what happens....

 

[sirzepp]

I checked all the diaphragms...they are all functioning as designed. The problem is still there...

 

[CalWheelin]

I checked all the diaphragms...they are all functioning as designed. The problem is still there...

i have the same exact problem but i didnt check to see if the petal moves when the truck is shut off.

i rebuilt my carb and after it would idle higher at around 1k. i pull the petal back and it goes back down but everytime you hit the linkage it goes back to a high idle. i havent tried to fix it yet but id think it might be fixed if you just take the carb back off and check all the linkage and make sure there is no binding and put it back on. i was thinking about putting a differant return spring on but thats a cheap fix to a easy fixed problem

 

[Altan]

i was thinking about putting a differant return spring on but thats a cheap fix to a easy fixed problem

The return spring just might be the problem. They do wear out and I've even seen them break. 20 years of flexing + being stretched to get it off and back on it might not have the power to overcome the venturi effect. but it never hurts to reinspect everything.

Good luck

 

[CalWheelin]

The return spring just might be the problem. They do wear out and I've even seen them break. 20 years of flexing + being stretched to get it off and back on it might not have the power to overcome the venturi effect. but it never hurts to reinspect everything.

Good luck

the thing is we both have the same problem. it worked fine before the carb was taken off to be rebuilt so its for sure that something is wrong.

 

[S&S1stCruzer]

I had a similiar problem, I followed Soggy60 steps. It took a few tries especially getting the choke to work again properly.

https://forum.ih8mud.com/showthread.php?t=181555


Hope this helps.

 

[sirzepp]

Thanks, guys, looks like I've got bigger problems than this...there is another thread about that. Suffice to say, I'm glad it didn't catch fire(found it leaking raw fuel out of the little valve on the lower driver's side). Anyway...I'll keep working on it.

 

[grant5127]

IIRC that little valve is over 100bux new..... or you can do as many have done and remove the guts and plug the hole where the plunger rod enters..... easy fix....

 

[brett76]

wehn i had this problem i had two vac lines crossed at the front of the carb

 

[orikawa]

linkage

brett, im having the same problem with the sticky linkage only while it's running. are you saying you had vacuum lines crossed on the carb and it caused this?

i literally have the exact same story about rebuilds, being at temp, pulling back at pedal and carb, high idle etc.

 

[PAFJ]

Look closely at your carb accellerator rod (#51 in pic below). If put on backwards after carb work was done, it will cause a high idle problem. On one end the ball joints are spaced further apart than the other end. This side should be on the carb side, the other the firewall side.

HTH-

 

[hank14]

On that diagram, is #63 the clip that holds the rod #51 and 53 in place? My clip is missing, and I need to know what to tell Dan to order another one. Thanks.

 

[Dave-T]

On that diagram, is #63 the clip that holds the rod #51 and 53 in place? My clip is missing, and I need to know what to tell Dan to order another one. Thanks.

Nothing special, just use a hairpin from the hardware store.

 

[brett76]

brett, im having the same problem with the sticky linkage only while it's running. are you saying you had vacuum lines crossed on the carb and it caused this?

i literally have the exact same story about rebuilds, being at temp, pulling back at pedal and carb, high idle etc.

yes

i had the first two on the front of the carb swapped