Stihl Saw Tuning

[bvaught]

I just installed the new vented front cover on my MS 440 Magnum. While I was at it I used the dremel tool to match the gasket and muffler inlet to the exhaust port.

Then on to the backyard Sunday night to pi$$ off the neighbors...er tune the saw. While adjusting the low speed ratio I discovered that the more rich I set the saw the better it seemed to idle. So I set it at the full rich position (factory stops still installed) and then used the LA adjustment to lower the idle a little bit.

At full throttle the saw four strokes, but just barely, and this corresponds with the factory setting on the high speed adjustment screw. My new tachometer doesnt get here until Thursday, so I will set the saw for max RPM then.

My question is does it sound like I am adjusting right? Im a little worried about having gone full rich on the low speed adjustment screw. I dont want to be too rich.

 

[Al Smith]

If you lower the back pressure,as you have,the idle has to be set richer.It's breathing better,now.If you look at that movie clip I sent in on that old Mac geardrive,you will see.That old relic has nearly open exhaust,and runs at around 9 thousand rpm,but when idling,blows black smoke,because of very little back pressure.

 

[Lawn Masters]

remove your limiter caps, adjust your H and L screws a little richer, then put the caps back on.