Operation Manual
91MS 240, MS 260, MS 260 C
– Position the end cover (1) so that 
the idle speed screw (arrow) is at 
the same side as the adjusting 
screws.
: Place the end cover (1) against 
the carburetor body from below 
so that the gasket and pump 
diaphragm are still held in 
position.
– Align the end cover (1) so that its 
pegs engage the holes in the 
carburetor body.
– Check that diaphragm and 
gasket are properly seated.
: Insert screw and tighten it down 
firmly.
– Reassemble all other parts in the 
reverse sequence.
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14.4.4 Choke Shaft / Choke 
Shutter
The choke shutter is in the air filter – 
see chapter on 'Air Filter' and 
instruction manual.
14.4.5 Adjusting Screws
Grommets have been removed for 
the sake of clarity.
There are three adjusting screws on 
the carburetor:
H = high speed screw (1)
L = low speed screw (2)
LA = idle speed screw (3)
If the carburetor cannot be adjusted 
properly, the problem may be the 
adjusting screws.
The high speed screw H has a 
limiter cap, which has to be 
removed before the screw is 
removed.
Always install a new limiter cap.
– Remove the carburetor, b 14.2
– See also carburetor 
troubleshooting, b 4.6
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: Pull off the grommets (1 and 2).
Low speed screw
: Take out the low speed screw (1).
– Inspect the sealing ring (1), 
washer (2) and spring and 
replace if necessary.
: Inspect the tip (arrow) for 
damage or wear and replace the 
screw (L) if necessary.
– Screw down the low speed screw 
(L) as far as stop.
– Continue with high speed screw.
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