Ms 660 Bogs when hot

[Sraponi]

Hey all! I have a ms 660 that starts up runs fine for a while, I can cut up little stuff with it and it's fine....if I set it on a sizable log and let it eat it starts to bog down and shut off after a min. Like when it gets hot it acts up. New air filter, spark plugs, fuel filters, bar and chain. Could it be a coil? I'd like to be able to fix it myself I'm pretty inclined to do so.
Thank you

[sawguy21]

Try turning the Hi speed mixture screw to the left a bit, don't over do it.

[Tacotodd]

I am also inclined to think the tuning may be an issue. Tune it a little fatter at a time until it slows down in the wood until it slows down some. Keep in mind, this is where a tachometer comes in handy.
 If you can have that elusive third hand then it would be easy. Good luck with your ongoing tribulations and I hope that you get it all resolved to your satisfaction.

TODD 

[Sraponi]

Thanks, I will give it a shot and let you know what happens

[John Mc]

If enrichening the mixture a bit as Sawguy 21 recommends does not do the trick, I would suspect the coil. My 357XP had similar symptoms. Ran fine when cool, but heat it up and it would have problems.