Outdoor Power Equipment (Lawn Mowers, Snow Blowers, Chain Saws and more) Discussions

tore the carb off a friends 35 yr old chain saw and cleaned  and reinstalled it because it would quit when the throttle was returned to an idle. ended up being the vacumn tube at the back off the carb was bulged at the fitting and leaking air.installed new hose and put back together. set the mixture screws each to  1 turn out(couldn't get it started) and then to 1 1/2 turns and it finally did start. once running i adjusted the low and high speed to mid point of lean and rich rpm drop and it starts and runs great,only problem is it will not idle down like it should.it runs slow enough to keep the chain from spinning but the rpm's are a bit high.i can back the idle speed screw out so the throttle plate is completely closed and it makes no difference. i can slow the rpm's by leaning the slow mixture jet  so i beleave they are not damaged or the problem. that's about all i know how to do! anyone have any ideas why it won't idle down like it should?

Can't help you too much with your queries.  It's been close to 30 years since I owned my Mac and while I did own it, didn't get much use out of it to remember anything of importance other than how shabby a saw it was. 

Generally speaking, I fill the oil reservoir with each fuel fill on my saws.  It's the safest way to do it. 

mkd55 wrote:

Borat is correct. Also, you can point the bar tip at a fresh cut stump or log and rev the saw for ~5 seconds, you should see little drops of oil spatter against the white wood. If not, turn it up some more.
In general you should go through almost a tank of oil for each tank of gas, at least on the saws I've had. Can't say it's the same for all brands.