I recently did a few updates to my MS 170 which included dogs, side tensioner, bigger bar and chain ( went from the standard .043 bar to a .050 bar and chain) and opened up the muffler. After opening up the muffler, the chain moves slightly while idling. I didn't upgrade to the adjustable carburetor and wondering if I adjust the idle screw if this would stop the chain from moving while idling and is it possible that it's running too lean after opening up the muffler and if so could this possible shorten the life of the saw?
Upgrading the MS 170
- Thread starter Hendog
- Start date
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Well, yes... and who mods a 170?
Me. I like to tweak all my saws for peak performance.
earlthegoat2
ArboristSite Guru
Opening the muffler will lean out the saw without a carb adjustment and yes it will also increase the saws rpm’s until you slow it back down by richening it up.
Playing with the idle may solve the chain moving problem but the chain moving is not the real problem. A leaned out saw is.
Playing with the idle may solve the chain moving problem but the chain moving is not the real problem. A leaned out saw is.
Have you tried to adjust the idle? You should be able to lower it as the one screw adjusts the amount of air bypassing the throttle plate. If that does not work, look elsewhere for a vacuum or pressure leak. If no pump and adapters, get out the can of brake cleaner.
No I haven't tried to adjust the idle yet, just started the saw for the first time last night after opening up the exhaust. I'll try that this evening. Just concerned if I leave the non-adjustable carb in how long the saw would last. I may have to upgrade to the adjustable carb after all.
WoodmanSr
ArboristSite Lurker
Hendon, you didn't share a complete picture. Are you using 50:1 fuel mix?
For example, 32:1 is detectable lean effect on idle & power. If your optimum performance is sub-50, try going back to routine 50:1 mix.
Oops, here comes the Amsoil ratio discussion. Please don't.
Yes 50:1
