Advice on bad starting Stihl MS211C

[Rich5ltr]

Hello, I have a Stihl MS211c which is a right bugger to start. This morning it took me about 15 mins to get it going and even then once warm and running the only way to restart it is to have the throttle open so that it revs straight from the off. Furthemore when using it if I release the throttle quickly it just dies so I have to very slowly decrease the revs before I can put the brake on to put it down while it is idling. After about an hour logging today, I finally couldn't get it to restart and so I gave up to come in for a cup of tea!

 

I have cleaned the plug and now ordered a new air filter but I wondered about just fitting a new carb'. So my question is: are all carbs the same or are their Chinese ones and German ones? I don't just want to go on eBay and buy something that's rubbish. 

 

It's so disappointing because I have a Stihl leaf blower that starts like a dream!

 

Thoughts? 

[5 shires]

Could be any number of things and it will be a process of elimination,first check if air leak as that’s usually the cause when you have to hold the throttle in to start it.Am sure others will advise you on other options and causes but you git to start somewhere.

[spudulike]

What age is your machine and has it run as it should since you have owned it?

Most issues on starting are fuel system related, followed by compression then ignition.

It would be good to pop off the muffler and check the look of the piston through the exhaust port. It should be grey and smooth with no vertical scoring/scrapes.....called seized.

Pull the plug out and look at the colour...tan is good, black is rich, grey means the engine has probably seized, white means it is going to seize.

You could turn the L screw out 1/4 - 1/2 turn and adjust the idle - saws from the factory are often set lean to meet EPA laws making them hard to start and having poor idle. You may just have a low idle setting. It should be set to idle evenly without stalling and without pinging the clutch or pulsing the chain forward. Try turning the H screw out by 1/4 turn, it may help.

If this is fine, your issues are probably carb related. I rarely replace carbs, I rebuild them as it is much cheaper than for my customers.

Things to check - The pump diaphragm flaps - make sure the holes in the alloy carb body haven't perforated them. Check the gauze strainer isn't full of fine chip. Change the fuel filter if the saw has had some use.

 

That should do it for now..........and report back with what you find.

 

[spudulike]

The short version of the above is that poor starting is generally down to lack of fuel or compression.

 

[Rich5ltr]

Wow, that's comprehensive advice there, thanks.

 

I bought it 2nd hand and it's probably about 5 or 6 years old. To be honest, I've always struggled with starting. I had the plug out and it was a healthy tan colour. I have a filter on the way so I will explore all those suggestions at the time I fit it. 

[spudulike]

What sort of condition is it? a bit ratty, clean and shiny near new looking....etc

When you pull the starter very slowly, when the piston is coming up to full compression, does the engine feel really spongy at the top end like there is a lot of resistance or is it relatively east to pull over? 

Take a pic of the piston through the exhaust port if you get that far, it will give us an indication of the saws condition. 

The plug colour sounds OK but will indicate flat out running and won't indicate how the saw works at idle. Hopefully it is indicating the engine is OK. 

 

Are you using the correct starting procedure, when cold - full choke, pull it over until the engine fires - typically 2-5 pulls, push the choke lever down SLIGHTLY to the FAST IDLE setting, pull it over until the saw fires - typically 1-3 pulls and pull the throttle open to get it back to idle.