Try adjusting both the high and low richer, turn counterclockwise around 1/4 turn or so. Most new ones are set real lean from the factory and when adjusted right will run good and make a lot more power. You might need to pull the limiter caps to adjust. Also try and get gas without ethonal. Steve

Check the spark arrestor screen at the muffler outlet. If it's blocked, heat with a torch or otherwise burn the carbon until it turns to white ash. Re-install.

A blocked screen will prevent the unit from revving UP.

Lemme try this again. When I first start the cs it starts
fine and runs loud and fast for the first cut. No stalling.

On subsequent attempts it will die when I give it gas,
UNTIL I just barely open and close the choke while running.
After that ONE choke, it runs great and loud and fast till
I am done. Just that ONE little period when it runs
badly.

So it's prolly not the screen as that would be continuous.
Ditto the carb adjustments 'cause they don't change from
the first, second, last running.

Are you using ethonal gas, my cheapskate BIL bought a can and his saw ran like crap and eratic, back to 92 without ethonal. It's not going to hurt opening the high and low adjusters a little and seeing if that helps, you can always put them backs where they were. I bought a new CS370 that had about the same power as my gutless Stihl MS170. After adjusting the high about 1/2 turn out and modding the muffler cut times went from 15 seconds down to 9 seconds side by side. It smokes my MS170 now. Steve

Steve, I just bought a new CS-370 and haven't even put a tank of gas in it. Would you please walk me through the muffler mod? Thanks.