My Stihl MS 211 was bogging down to the point it was useless so I adjusted the carb. I set it to what the manual said, H : 3/4 ( which was also max I could get with the limit cap installed) and L: 1. It did not help. I pulled off the limiter cap on the H , screwed it in and set it 3/4 out and it runs perfect to me but what do I know. My question, when I set it to H : 3/4 out without the limiter cap installed, am I suppose to go out even more? I did not pay attention exactly how far out the screw was when I took off the limiter cap and did not know if there was any change in spec because of the cap or no cap.
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Stihl MS 211 carb adjustment question
- Thread starter johninct
- Start date
5ubtle
Well-known member
I am not a small engine mech, so take that into account when considering my advice.
It is my belief that the limiters are a "government regulation" kind of thing to keep owners from making their saws belch smoke. If the saw is in good condition, the saw will run well within the range of the limiters. The manual has specs for "initial" screw adjustments. Don't be surprised if the "initial" settings aren't the best. The "initial" settings will allow the saw to start, but then you need to tune if from there.
If your saw needed the limiters removed to run good, something else is probably "not quite right". My guess is that the carb is gummed up somewhat, or that the diaphragm or checks in the carb have become stiff.
It is my belief that the limiters are a "government regulation" kind of thing to keep owners from making their saws belch smoke. If the saw is in good condition, the saw will run well within the range of the limiters. The manual has specs for "initial" screw adjustments. Don't be surprised if the "initial" settings aren't the best. The "initial" settings will allow the saw to start, but then you need to tune if from there.
If your saw needed the limiters removed to run good, something else is probably "not quite right". My guess is that the carb is gummed up somewhat, or that the diaphragm or checks in the carb have become stiff.
It takes the smallest little piece of debris to plug a port in your carb(90% of the issue with 2 stroke engines is starvation). Either clean the hell out of the carb or replace it, and make sure there is no restriction in fuel system, or air getting in(cracked primer, fuel line, etc.)
LopezBart
Well-known member
According to the manual, two different carbs are installed on these saws at the factory, each w/ different procedures.
And, of course, check the air cleaner, exhaust port and spark plug. And drain it and run the gas out of the carb if it's going to sit for more than a month. And run alcohol free gas if you can get it.
And, of course, check the air cleaner, exhaust port and spark plug. And drain it and run the gas out of the carb if it's going to sit for more than a month. And run alcohol free gas if you can get it.
I had heard that the 91 or 93 octane had less ethanol. Not 100% positive of that but either way less ethanol, alcohol, is the ticket to a long lasting 2 stroke.According to the manual, two different carbs are installed on these saws at the factory, each w/ different procedures.
And, of course, check the air cleaner, exhaust port and spark plug. And drain it and run the gas out of the carb if it's going to sit for more than a month. And run alcohol free gas if you can get it.
Wamsutta
Well-known member
Your 3/4 turn out High and 1 turn out Low are the bench settings to get the engine started.
After the engine is started and fully warmed up, then you fine tune your mixture from there while it's running.
After the engine is started and fully warmed up, then you fine tune your mixture from there while it's running.
finn
Well-known member
Your problem is that the internal passages are partially plugged, or maybe your carb has an internal screen that sometimes gets plugged with wood fibers.
By futzing with the adjustment screws, you’re masking the real issue and will never get it to run right.
tear down the carb, clean it, and do a proper rebuild, or buy a new Oem carb.
I’ve been down this path.
Also, check the spark arrester screen in the exhaust for fouling.
By futzing with the adjustment screws, you’re masking the real issue and will never get it to run right.
tear down the carb, clean it, and do a proper rebuild, or buy a new Oem carb.
I’ve been down this path.
Also, check the spark arrester screen in the exhaust for fouling.
The mixture screws are also used to set the maximum operating RPM; Stihl also doesn't want it to be too lean. I worked at a few small engine shops in the 80s-90s, and once we got a digital tach, new and expensive technology then, we realized that we were always setting the carbs slightly too lean, because we were going by ear. They sounded good, but we were also running the engines over the max intended operating RPM. I don't remember the saws having limiting caps back then, but limiting caps were used on some automotive carburetors even in the 1960s; of course, they were all pried off on day two...
Anyway, I agree that if you had to remove the caps to make it run properly, something is probably wrong with the fuel system. Because it probably worked fine on the initial settings until recently. Small engine diaphragm carburetors are extremely finicky, because they're so tiny.
Anyway, I agree that if you had to remove the caps to make it run properly, something is probably wrong with the fuel system. Because it probably worked fine on the initial settings until recently. Small engine diaphragm carburetors are extremely finicky, because they're so tiny.