[MOBLO1]

i have a stihl cutoff saw that won't run in idle. Is the screw below the fuel adjustment labeled LA for low altitude?
what is the correct setting for this?

[synner]

what model of Stihl saw are we talking about?

[johnkeegan]

Also check the "exhaust screen filter" (spark arrestor?). It can get plugged with carbon deposits and cause the symptons you mentioned. Just pop it out burn and/or scrap off the deposits and reinstall. Might help.

[synner]

just pop it out and leave it out. we end up doing that with all our stihl trimmers, blowers and cut off saws.

[MOBLO1]

the model stihl cutoff is ts450. I was told it might be sucking air and there is a pressure testof some kind that might find the leak. Is there a tool I can purchase or what is the procedure?

[johnkeegan]

Did you try removing the spark arrestor screen and changing the fuel filter in the tank/ then mix and add fresh fuel/ change plug..

[siduramaxde]

Originally posted by MOBLO1
the model stihl cutoff is ts450. I was told it might be sucking air and there is a pressure testof some kind that might find the leak. Is there a tool I can purchase or what is the procedure?

Usually if they are sucking air (i assume from the carburator boot) they tend to rev real high because of the lean fuel mixture. The screw that is labled LA is the idle speed adjustment screw. I believe there are 3 screws(idle speed, low speed, and high speed) the biggest one is the idle speed screw. I'm not sure if adjusting this screw will fix your problem or not. It could be that your spark arestor screen is plugged or I have even seen torn fuel lines and carburators that need to be rebuilt.

Good luck

[Bill Schwab]

The easiest way to check for an air/vaccum leak is to get a can of carb cleaner with that long straw type nozzle. At as low of a speed as you can get, typically dead idle, you spray the carb cleaner all around the boot and connections where the carb meets different surfaces. If there is an RPM increase, you have a crack, loose nut, etc. etc.

I'm not sure what tier classificagtion the ts 450 Stihl saw is listed as, but tier 2, 2 cycle engines as well as C.A.R.B. compliant engines would have fixed jetting. The only adjustment is goingt o be the idle. That leaves clogged internal filters, jets, etc. Cut off saws are in so much garbage and dirt they clog easily, especially when they are refuled in dirty conditions.

Just a few things to check.