Stihl 044/046 idle screw super loose?

Brock Mayo

Brock Mayo

TreeHouser
Joined
Dec 3, 2012
Messages
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Cottage Grove, OR
Hey all,

Having some carb issues on a 044/046 (has some parts from both?). I think my issue is the idle screw is super loose, I can easily spin it with my fingers. Doesn't look like the idle screw on those carbs had a spring for tension. Any thoughts on getting a little friction onto that screw? Tried a tiny wrap of teflon tape, seems like the residual carb cleaner is eating it right away. Maybe let a little low strength locktight fully dry on the screw and then reinsert? Thanks

Brock
 
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  • #3
Do you have a product I could look at? Not sure what kind of string is used on pipe threads... I've only used tape and dope
 
Take the screw out, take a hammer and punch and slightly distort one of the threads in the hole. Reinsert screw and reset. The idea is to distort one thread enough to create enough friction to keep the screw from turning easily.
 
I mark were it supposed to sit and wreck one or two threads just were screw enter so it sits.
It is loose as the threads are worn in carb house, most often. Not uniqe and happens on many saws with this type of idle screw, regardless of brand/size/model.
 
Brock Mayo said:
Do you have a product I could look at? Not sure what kind of string is used on pipe threads... I've only used tape and dope
Click to expand...

We just used kite string on 2” and bigger screw water/air line. Rayon does good on not so harsh chemicals. I have a roll of angel hair solder I got at Radio Shack years ago that works great on small screws. It’s only .015”. If it’s a Ford or Chevy screw just beat on the screw threads with a rock... ;)

43667D32-C60F-49A2-8951-41DB802D5FAA.jpeg

Deforming the screw threads should be a last resort, it will possibly ruin the threads in the carb.
 
Solder them I have tried, it has same affect as whacking thread on screw.
I re-threaded and put a larger screw ( in correct shape) in a couple times.
I replace housing most times as I often have spares.
In rare occasion I put new carb on.
 
If threads in carb are wallowed out then a cheap fix may be to wrap the threads with pipe tape as needed. If this doesn’t work remove carb from unit and install a tang type hell-coil insert
 
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  • #13
Yeah I might try the pipe tape again. I maybe went a little light the first try... What is a tang type hell-coil insert?
 
This is not a engine block bolt that needs a lot of torque. Carb housing is casted so this is a bit outside housing and pretty weak, brittle and pretty narrow. Re-threading to a larger diameter hole makes it even more so. But as its a idle adjustment screw that is not under much load and that sometimes work.
Setting inserts or helicoil is not the best idea, better to just put in a larger screw in correct shape.
 
Agreed ... If threads are wallowed out such that there is no purchase then maybe a new carb is in order. A small heli-coil may work in this instance but the needed tools can be pricey
 
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  • #17
Good link, I'll have to work helical inserts into some casual conversation. Last question, what is the point of the small hole (tooth pick diameter) that runs perpendicular to the screw? It seems like a tiny plastic dowel or something like that could sit in the bottom and put a little side pressure on the idle screw to keep it from moving?
 

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These carbs use same house for a large amount of variations. That hole may have some purpose in an other version of carb.
Its nothing I could see in parts list.
What carb model number is this? HDxxx?
 
A newer one than the IPL I looked in. Zamas C3M look about the same as HD.

As long as screw stay were it should its all well. Tape work sometimes very well.
 
I have some very thin brass sheet scraps, - less thickness than a piece of writing paper, almost like a strip of tinsel off the old Xmas tree (but don't use tinsel, chrome-plastic melts). I cut a small strip less than 1/4 the circumference of the threaded hole, slide that part-way in and thread the screw in. It readily forms to the thread profile without distorting the threads of the carb or screw and tightens it up nicely.
 
  • Thread Starter Thread Starter
  • #23
That brass sounds handy. Maybe I can hammer some copper into a nice thin strip. I'll be sure to waste a lot of time before I break down and buy a new carb :)
 
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