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ZS Carb adjustment

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TRclassic3

TRclassic3

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I decided my ZS carbs needed some attention and purchased the mixture adjusting tool. When I attempt to adjust the front carb the tool is difficult to turn but it will turn with moderate force. The rear carb will not turn at all in either direction with strong force.
Am I missing a step or do I have a problem with these carbs? My expectaion was that the adjustment would turn relatively easily.

TIA
 
Some times they don't. There are a couple of possible reasons.
The star washer may have gotten cockeyed and wedging the adjuster.
The rubber O-ring may have deterioated and stuck against the wall of the damper well.
The adjuster may have been turned clocwise fully and then some, making it extermemly tight.
What I do when I get one like that, is remove the air valve/ diaphram/ needle assembly as a whole, right out of the carb so I can grasp the air valve in one hand and turn the allen wrench with the other.
Prior to that I use a brass rod to see if a few taps will seat and align the star washer properly.
Still,.. it may take some torque to get the adjuster working again.

And incase you aren't aware. From a full rich (clockwise) adjustment to the point where the needle becomes unthreaded from the adjuster is a mere 2-1/2 Counterclockwise leaning turns.
After that there will be no needle movement,(although the needle will still be trapped in the air valve), until you reengage the threads.
 
Thanks for the info. I'll pull them apart as suggested. I was aware of the amount of adjustment. What I was trying to do was adjust all the way in and then back out 1-1/2 as a starting point. Also to get a feel of where the adjustment was currently set. What would the tool feel like if the it had been backed out and no longer engaged?
 
Don't forget, the adjusting screw is brass and strips easily. If you can get it to turn at all, my suggestion would be to disassemble and replace the O-ring. Tapping is a good idea, and soaking in solvent or penetrating oil (to soften the O-ring) might help as well.

If the needle carrier is protruding, you might be able to turn it off the adjusting screw (after removing the retaining screw of course).
 
Ed, after the adjuster and the needle become disengaged, the allen wrench turns freely. That is if it was turning freely before it disengaged.
In otherwords you won't be albe to tell a difference except that the needle itself won't respond.
 
My money's on a craminated o-ring. Melted/glued in place. R&R pistons and disassemble to replace the o-rings. The Allen wrench should be easy to turn and as these other guys mention, the adjuster is soft and WILL strip out if forced.
 
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