On Sat, 10 Apr 2004 16:39:41 +0100, "Juco"
wrote:

My hedge trimmer( McCulloch 2 stroke) cuts out on idle but runs fine on full
throttle but if I cut a section then go back to idle cuts out and difficult
to start unless I leave til cold again. Plug has been changed. I noticed
there are 3 adjusment screws. 1 I no for to speed the engine up the other 2
are marked "hi" and "lo".
Anyone got ideas I think just a tweak to get it right (I hope)

thanks

This is the usual generic setup for chainsaws etc. They should be set
with the engine warm. The one on its own is 'idle speed' - set so it
idles without stopping and blades are stationary. Lo is mixture for
slow running - set so it idles sweetly (you might now need to reset
slow running speed) Hi is correct mixture for full speed/power - set
this with throttle full open, tweak 'til revs peak, then back off
slightly 'til the revs drop a little and engine sounds more
comfortable and giving off very little smoke (professionally this is
done with a tachometer to set maker's recommended correct revs - if
it's set for absolute peak revs you're thrashing it and the mixture is
too lean, runs hot and lubrication breaks down - bang! oops! That's
why you back off from peak revs.)
You might have to go through this a few times to get it just right.

*Before you do anything*

Check your starting settings ie atm it will start at least, so you
need to be able to get back to that condition if you mess things up.
For each jet in turn notice the position of the screw slot then turn
it clockwise 'til it stops - note the turns you made, ie half,
threequarters, one and a quarter - whatever, and note it down then put
the screw back exactly where it was. Now start it, check it's behaving
as it was before - now you know you can get back there and can start
messing about without fear of ending up with a machine you can't
start.

Rod

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