Husky 257 idle speed too high

[ZR900]

Appears to click out of cold start high idle. Set screw is backed out and it does make a difference if I screw it in. I haven't pulled the carb for a look. Saw works perfectly otherwise. Dangerous to operate as the chain is flying at idle.

Thoughts?

[ZR900]

By set screw I mean idle speed adjustment

[dougand3]

Multiple possibilities:
Air leak - gotta find area - intake or crank seals
Carb too lean - fatten L screw 1/8-1/2 turn CCW
Clutch springs too weak and engaging too early - need to inspect

[ZR900]

I tried the low speed adjustment. I can make the saw slow down but it's due to turning it too far in. It acts like the throttle is up a bit. Runs fine. Just too fast. If the crank seal was bad would it run fine? It cuts great. We've been using it. Just too *DanG dangerous with the chain going around. It'll snag your leg and stop but it's hard on carharts.

[ZR900]

Would the saw run good with a bad gasket in front of the carb?

[dougand3]

Let's check procedure. Turning L in = Clockwise - going leaner. Saw will slow down due to lack of fuel. Turning L out = CCW and richer.  Saw will slow down when it gets close to flooding. About halfway between the lean bog and rich bog is normally a good point. I usually give a 1/16 turn CCW/richer from that point to insure enough fuel lube. Once L is dialed in, then Idle (TAS, LA) screw is adjusted for no chain spin or a little tick, tick, tick.

A saw will run great and fast in a slightly lean condition. But damage can result from poor lube.

If the carb is where it should be - gotta be the clutch.

[realzed]

I know if I need to check auto engines for vacuum leaks around the carb bases or intake manifold gasket areas a can of WD40 spray or carb cleaner with a nozzle pipe or hose to direct a small stream of spray close in where you suspect a leak - while listening for idle speed changes.. will tell you a lot about the integrity of the gaskets and seal. Usually if the idle changes when an area is sprayed, it means there is a leak sucking in the atomized material and either burning it which leads to a higher speed or if it is a spray that isn't as flammable as a fuel/air mixture, it results in a drop in idle speed on a leaking gasket or seal where momentarily it helps seal up a leaky area..
Lots sprayed all over, obviously doesn't tell much and if anything can produce false or confusing results especially in such a small area as in a chainsaw application - but a quick snort near a carb inlet sleeve, base/case/ gasket area or crank seal might tell you a quick and easy story!