Stihl MS211 carb adjustment

[Boogerhook]

Got bored today, so I pulled the muffler off my MS211 and punched a few holes in it and also shaved the tab off of the H limiter. Using a tachometer and my un-finely tuned ear, I let it get warmed up and then started adjusting the carb.

Before any adjustment it was idling at about 3500 rpm, so I backed out the LA screw until it was bouncing around 2800 rpm. After running the L screw in and out a bit I decided that its original position was correct, and went on to adjust the high side.

At WOT, it topped out at about 13500 rpm and I started running the H screw in, expecting to hear the engine lean out and RPM to increase. Speed remained fairly constant and I couldn't hear any difference so I took the screw back to its original position and started backing it out. RPM did start to fall off a bit, but I didn't hear it begin to burble like the 029. I ran it back in to the original position, at 13500 rpm and called it good.

My question is should I expect the 211 carb to react differently to tuning than the 029 carb? The 211 acted like it had a limiter which prevented going over 13500 rpm, but would that also keep it from responding to a lean or rich condition at WOT like the 029 would?

 

[HarleyT]

Here is a pic of one...

 

[windthrown]

I have found that to be the case with most of these strato air-injected saws. They are all nearly impossible to tune the old school way, even with a tach. So I richen the H jets up a tad from what would otherwise be full lock before the limiter tabs are trimmed off and leave them there. Compare them to my pre-EPA 036 which I can tune perfectly in about one minute flat with or without a tach.

 

[Boogerhook]

I have found that to be the case with most of these strato air-injected saws. They are all nearly impossible to tune the old school way, even with a tach. So I richen the H jets up a tad from what would otherwise be full lock before the limiter tabs are trimmed off and leave them there. Compare them to my pre-EPA 036 which I can tune perfectly in about one minute flat with or without a tach.

That's pretty much where I ended up leaving my H jet at. Since I couldn't hear the response from the engine that I expected, I was worried about leaving it too lean and burning something up. I'm going to take it out tomorrow, and I'll check the plug after the first tank to see what it looks like.

I'm still pretty ignorant about the intricacies of 2-cycle engines, and the differences between pre- and post-EPA. Thanks for the response.

 

[windthrown]

Well, I had not thought of the coils being limited, which may be the case on these guys. No one seems to know of the 211 saws have rev limiters or not. The service manual does not say anything about it being limited.