After sitting up over the winter my Mcculloch 2816 string trimmer restarted rather easily (I did use fresh gas and the 40to1 gas-to-oil mix), but now, compared to my end of season use last year, the trimmer seems severely handicapped with less power, less high speed rpm. (When I finish using
the trimmer, I have always drained out the gas tank, tho I rarely ran it till it's out of gas; perhaps this is the problem?? ...after almost
10 years of use like this...?) The law here in AR doesn't require me to have a spark arrester, so there is none; I've cleaned the air filter, but haven't done anything with the fuel filter -- ever. The spark plug is gapped correctly: .025" . What's wrong?

winnerarkansas, April 2006

I had the same problem and cleaned the spark arrester screen and that took care of the problem!

Carl, June 2009

If your spark arrestor on your exhaust is clogged it will not rev,remove it with one screw clean the screen reinstall and your off to the races

Top Robinson, September 2007

rebuild carburator , diaphragms get stiff over time
esp if you use reg gas ,use at least medium grade
less alcohol preserves lifespan rebuild kit 10 bucks at
your friendly small eng rep ie true value do it slow
and take notes of the order the parts disassembly
diaphram goes on carb face , then gasket and cover
may have to set needle valve

jo dude, April 2006