Stihl MS211 - will not rev

[Toad]

This is one of those jobs I really wish I'd not started, but it's too late now.

 

My sister's father in law has an MS211 which has started running poorly apparently. I don't expect it has been looked after and I assume will have had old fuel sat in it for some time.

 

I got hold of it and couldn't start it. Didn't seem to have a spark, so fitted a new coil and plug, few pulls and it starts on choke, cuts out, starts on the half throttle position and then idles after a quick pull of the throttle.

 

The saw will idle for some time although occasionally cuts out but if you open the throttle it'll cut out and die.

 

I've reset the high and low screws to 1 turn and 3/4 turns out as per the casing and it idled better but still doesn't rev. 

 

I've pulled the exhaust off and the piston looks fine.

 

I assume to start with I should fiddle with the low and high screws to see if I can get it to behave somewhat better, but has anyone any ideas about what I should be checking on the saw. I know my way around the husky 3 series, but never done anything with a stihl before.

[Toad]

Actually, now I've gone back to fiddle with it. It won't even stay idling for any length of time properly. Seems happier when on its side, starter up.

[DCS6800i]

Our 210 did this a while back. It had done a hell of a lot of work with zero maintenance (if it ain't broke don't fix it...) 

 

Change out the carb. A new one is almost as cheap as a gasket kit. Check the fuel lines at the same time.

[Toad]

It does 'feel' like fuel starvation. Carb settings don't make it any better, but do make it worse.

 

I did pull the carb off and clean it, wasn't much wrong as far as I could tell, but when checking the fuel filter I did notice a leaf floating around in the tank, so a more thorough flush of that is required.

[spudulike]

If it idles but dies when you open the throttle then it will be fuel starvation. Change the fuel filter and while you are in there, check the state of the fuel line - if it looks OK and isn't hard or cracked, try that but I think it is mpre than likely that your carb gauze strainer has fine wood chip in it or a fine scum dried on it. Pull the carb off, take off the alloy cover held on by one large screw, prize the strainer out (sharp craft knife), look through it with a magnifying glass and if blocked, carb cleaner and compressor to clean it. Reinsert, reassemble and retune carb.

See how that goes!