Troubleshooting, Problem possible cause solution – Homelite MIGHTYLITE UT21907 User Manual
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TROUBLESHOOTING
Problem
Possible Cause
Solution
String will not advance.
String is welded to itself.
Not enough string on spool.
String is worn too short.
String is tangled on spool.
Engine speed is too slow.
Lubricate with silicone spray.
Install more string. Refer to
String
Replacement earlier in this manual.
Pull strings while alternately pressing
down on and releasing spool retainer.
Remove string from spool and rewind.
Refer to
String Replacement earlier in
this manual.
Advance string at full throttle.
Spool retainer hard to turn.
Screw threads are dirty or damaged.
Clean threads and lubricate with
grease – if no improvement, replace
the spool retainer.
Grass wraps around driveshaft housing
and string head.
Cutting tall grass at ground level.
Operating trimmer at part throttle.
Cut tall grass from the top down to
prevent wrapping.
Operate trimmer at full throttle.
Lubricant drips from muffler.
Operating trimmer at part throttle.
Check lubricant/fuel mixture.
Air filter dirty.
Operate trimmer at full throttle.
Use fresh fuel and the correct 2-cycle
lubricant mix.
Clean air filter. Refer to
Cleaning
the Air Filter Screen earlier in this
manual.
IDLE
ADJUSTMENT
SCREW
Fig. 19
idle speed
screw
slow
fast