High and low speed carb adjustment instructions FS 45

marlo52 · Jul 31, 2017

I'm having a problem with Stihl's instructions for adjusting the high and low speed screws on the carb for my FS 45 trimmer. Everything but the first statement is straight forward and clear.
However, the instructions for the H control says "turn H CCW as far as stop (no more than 3/4 turn)" . My H adjustment turns CW (not CCW) to get to stop and the "no more than 3/4 turn"
makes even less sense - depending on where the adjustment screw is setting, it could take several full turns to get to the stop position. If the statement instructed to turn H CW until reaching
stop, than turn back CCW no more than 3/4 turn, it would all make sense. Can anyone shed some light on this ?

Stikl's instructions and a pic of the carb are shown below :

Boobala · Jul 31, 2017

I sure THAT circled statement is a mis-print , Normally the carb. screws turn C/W to close , SNUG, NOT tight, the suggested number of turns OUT is usually from the closed position, your picture doesn't show the screws , I believe that's the diaphragm cover. It could be construed going CC/W 3/4 turn to the stop means the "limiter cap is in place"

bertsmobile1 · Jul 31, 2017

marlo52 said:
I'm having a problem with Stihl's instructions for adjusting the high and low speed screws on the carb for my FS 45 trimmer. Everything but the first statement is straight forward and clear.
However, the instructions for the H control says "turn H CCW as far as stop (no more than 3/4 turn)" . My H adjustment turns CW (not CCW) to get to stop and the "no more than 3/4 turn"
makes even less sense - depending on where the adjustment screw is setting, it could take several full turns to get to the stop position. If the statement instructed to turn H CW until reaching
stop, than turn back CCW no more than 3/4 turn, it would all make sense. Can anyone shed some light on this ?

Stikl's instructions and a pic of the carb are shown below :

View attachment 33608

IT is a thread.
Threads turn in both directions
if yours is already full CCW then you are where you should be before you start
If it is anywhere else ans will only turn the wrong way then the needle is damaged or someone has pulled the cap & replaced it in the wrong position.

marlo52 · Aug 2, 2017

Of course, the screw turns both ways. But, continual CCW turns will remove the H screw.

Boobala · Aug 2, 2017

marlo52 said:
Of course, the screw turns both ways. But, continual CCW turns will remove the H screw.

just as continued C/W rotation will bottom it out to the closed position, BUT, only if the limiter cap is removed .

High and low speed carb adjustment instructions FS 45

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