What oil to fuel ratio are you using?

[arto98607]

I run everything 40:1. Dealers cant tell you different either due to epa law.

But knowing a few dealers that are in the know. They will tell wink wink if they trust ya. They run their stuff 40:1 min.

Look for FD oil IMO too.

Always tune to your mix. AT or MT will do it for ya.

Congress creates laws - EPA makes regulations & mess

Just saying.

 

[RandyT]

Many Stihl shop manuals describe how to tune that particular engine using a tachometer.

Most have always had a max rpm listed in the manual and recommend that it be tached. With todays saws with the variable spark timing and electronic rev limiters a tach is almost required to tune one. Too easy to go too lean and not realize it without a tach to measure rpm's and if you have exceeded the rev limiter or not. Some saws will sound like they are 4 stroking at the rev limiter which could indicate to some people that it is running too rich but in reality is too lean already. Some are not as noticeable and will only show up as a fluctuation in the rpm on the tach.

 

[ericm979]

Yes the difference between fourstroking and hitting the limiter is pretty subtle. Rather than listen for four stroking while it's free revving, I listen for it when I lift while in a cut. For me that's more reliable. Also I prefer not to free rev an engine at full throttle.

My Stihl manuals spec an idle rpm, a full throttle free rev rpm, and describe how to correctly set each one. The idle adjustment winds up a little richer than what you'd get by just setting the rpm, and that improves starting and throttle response when you open the throttle while its idling.

 

[90cummins]

I agree that the higher the oil to gas ratio the leaner the engine will run, however if the carburetor is readjusted to compensate no problem.