The Forestry Forum

General Forestry => Chainsaws => Topic started by: minesmoria on October 04, 2005, 11:18:32 PM

Title: New saw adjust
Post by: minesmoria on October 04, 2005, 11:18:32 PM
I have ran two tanks of gas in my new husky 359, i have a techometer and plan on setting the high  speed to 13 500 per specs

But i have one of those walkerized mufflers would this mean i should set it less say 13200?
Title: Re: New saw adjust
Post by: fishhuntcutwood on October 05, 2005, 03:28:11 AM
Quote from: minesmoria on October 04, 2005, 11:18:32 PM
But i have one of those walkerized mufflers would this mean i should set it less say 13200?

Quite the opposite.  Opening a muffler, via an enlarged port, a dual port cover, or via Walkers it allows the saw to run faster, which is one of the benefits...but not too much faster.  This is where a guy needs to know how to tune a saw by ear, and in a cut.  After the muffler is opened, the baseline RPM numbers are no longer valid, as you're now allowing more air through the saw.  There's a good tutorial on Madsen's website.  Do a search on here, and you'll find the link.   

If you just open the muffler and don't adjust the carb, it'll be running lean and fast.  This is where you need to richen it up, but you need to richen it relative to the opened up numbers, and not the stock numbers.  Say it runs 13,5 stock, and now it runs 14k opened.  You'd richen it up relative to the 14k, which would put you somewhere around 13,7 or 13,8. (These are all just random numbers I'm throwing out for examples sake.)

You'll need to tune the saw by ear and in wood to get it running right.  If you set it to 13,5 or 13,2 with an opened muffler, you'll be way rich, and way rich is bad on a saw too.  Tune it by ear, and then use your tach to make sure you aren't screaming along at 15k.  Tune it, run it, and then check it.  If you try to tune an opened saw to a certain number with a tach it is a shot in the dark. It really is with any saw, but more so with an opened one.

Jeff