You will need to know the basic setting for the saw carbs
L & H adjustments, this can be got free from the saw manufacturer via their web site IE download the saw manual.The settings vary 1, 11/2 to 2 turns from the point where they seat, be careful that you don't turn in too hard as you will damage the valve.
Before you finely tune the saw the air inlet on the cowling should be free from debris and the air filter must be CLEAN with the engine left to run until it is hot.
There will be three settings on the carb :- T : L & H
This should give you a chance to start the saw, then adjust the L setting first this gives a smooth tickover.
Turn it slowly a quarter turn either way untill the saw revs at its highest point on tickover then turn the screw a 1/4 turn counter clockwise ( to the Left ), then with the brake off adjust the T setting until the chain revolves freely around the bar then turn back until the chain is stationery ( stopped ).
Finally adjust the H setting, first rev the engine at full speed for 10seconds and turn the H screw a 1/4 turn anti clockwise.
Run the saw again at full revs for 10 seconds and note the difference in engine sound, turn the H screw a further 1/4 turn anti clockwise and again rev the saw for a further 10 seconds.
At each stage you will have noted a different engine sound.
set the H screw at the point where the saw 4 cycled a little if the saw whistles the setting is too lean, if the exhaust gases are too rich when it 4 cycles the mixture is too rich,
It should not be too difficult to get somwhere between the two settings but run it richer rather than too lean as the saw could be damaged otherwise.
It is a matter of using your ears, a more accurate setting can only be achieved by using a tachometer or ultimately return it to a dealer for a tune!
The screw driver used for setting carbs has a nodule or mark on the handle so you can more accurately gauge the turns you are making while making adjustments it should also be fine enough to easily access the adjustment screws.
Good LucK ( PHEW ).
Regards! Arthur Bradshaw : braddersx@yahoo.co.uk.
A. L. Bradshaw., March 2006
