# Ms 291 muffler mod instuction



## Craig Harmon (Jan 17, 2016)

I bought A new new ms291 and hear all this talk about a muffler mod but can't find any detailed instructions any help would be appreciated! Thanks


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## Hoowasat (Jan 18, 2016)

Try asking your question in the CHAINSAW section of this forum ...
http://www.arboristsite.com/community/forums/chainsaw.9/


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## Craig Harmon (Jan 18, 2016)

Hoowasat said:


> Try asking your question in the CHAINSAW section of this forum ...
> http://www.arboristsite.com/community/forums/chainsaw.9/


Ok thanks!


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## Clyde S. Dale (Feb 8, 2016)

You need to either expand the size of the factory hole of your muffler or add another. I don't know the setup of the muffler of the MS291, but suspect since it is a new model the factory muffler is rather choked up and it would respond well. Rule of thumb for muffler mods is the exhaust hole or holes should be about 80% the size of the exhaust port on your cylinder. You'll also need to re-tune your saw once done and richen up the H screw (counterclockwise turn). When you go to do this you will run into limiter tabs that will need to be defeated so you can richen the tune. Like Hoowasat mentioned your best bet is to post the question in the chainsaw forum. You can also try using the search function of this site as I suspect others before you have asked. It would also be good to read up on saw tuning. Good luck with your modification, sounds like CAD starting to take hold.

Clyde


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