Stihl MS 211/ C help needed with conking out and flywheel issue

1964johnr · April 12, 2019, 06:33:12 AM

My brothers 10 year old saw which has relatively little use. I buy a service kit once a year to service it for him and have sorted a few minor issues with replacement parts in the past. This time I'm stuck and need pointing in the right direction. The saw started cutting out soon after starting, which got worse and now doesn't start at all. In addition, the flywheel rotates when pushed by hand, but gets stuck and needs some force to free it. I can't pull the rope to try to start it because of this issue. There doesn't seem to be anything wrong with the rope or the mechanism. It works freely with the flywheel cover off. The spark plug was quite oily as was the area behind the air filter. I am thinking that perhaps it is a flywheel issue and something else. I am hoping it's not the piston. There dont seem to be any fuel leaks or oil leaks. We are carefull to get the correct fuel/oil combination. Can anyone suggest how I might diagnose the problem(s)? My initial thought was fuel supply issue, but now I have encountered the flywheel issue I'm thinking something else.

Mapleman · April 12, 2019, 08:14:38 AM

I'm wondering if the saw isn't hydro locked, which occurs when the cylinder has way too much fuel in it and the piston can't compress the fluid so it stops part way up. You can check for this by taking the spark plug out and seeing if the saw will pull over then. If this is the case I don't have any wise words on what might cause it or how to fix it, but I'll bet someone more knowledgeable will come along and help out.

limbwood · April 12, 2019, 09:52:39 AM

might want to take off the muffler and look at piston and make sure it isnt scored

ladylake · April 12, 2019, 09:54:50 AM

Also look at the muffler screen, they like to plug up on those saws. Steve

luap · April 12, 2019, 03:28:07 PM

check that the screws are tight on the coil and that you have proper clearance between coil and magnets on flywheel. about the thickness of a business for a ballpark number (.010)

Inaotherlife · April 12, 2019, 04:02:17 PM

Yeah, if it's not seized, it should pull over with the spark plug out.

Too much fuel, or possibly bar oil getting in the crankcase somehow?

1964johnr · April 13, 2019, 01:11:23 PM

I posted yesterday and had some useful replies, so spent a few hours today trying to find the issue(s) with this saw which started running erratically and then was hard to start at all. I have run a few checks which were suggested. I checked the spark plug which seemed quite oily. I took the air filter out and checked it, it seems fine. I withdrew the plasic housing for the air filter and there was a lot of sawdust and oil on it. I took the carb out. This was also covered in sawdust. I took the plate off the bottom of the carb to check underneath. The plastic screens were fine and there was no sawdust under the plate. I took the muffler off and there were lots of carbon deposits at the air outlet. Looking at the piston through the exhaust port with a magnifying glass showed a browny gold colour in places and some scoring, perhaps 6 or 7 vertical scores. I am by no means an expert so dont know what level of scoring would indicate a piston and cylinder case issue. I dont have a compressure device to check this. I put it back together, put some fuel back in the tank and thought I would crank it up and see what happened. I started it on cold start because it wouldnt start on the normal start position. It coughed and spluttered, spat out white smoke, started to rev very quickly for a few seconds and then conked out. When I picked it up there was a puddle of oil underneath which had not happened previously. Any experts out there with any ideas as to what the issue might be. My fear is the light scoring on the cylinder could be the problem.

If it is the piston/cyclinder getting it repaired would seem to be not economical unless I do it myself. I have seen after market parts on line. Can anyone tell me if the unit can be purchased with the piston, rings etc already assembled inside the cylinder and if so is this job doable for a capable DIY er. Any help would be appreciated.

Al_Smith · April 13, 2019, 06:51:47 PM

I had to look the thing up,it's too new for me .It's an itty bitty little thing like 2.15 cubic inches .It's a low emission engine which I know nothing about .However about the only thing that would excessively carbon the thing up would either be extremely rich oil in the gas or extremely rich carb setting . Other than that I know nothing about those carbs .

dougand3 · April 13, 2019, 10:51:51 PM

The oil underneath may be the oiler working.
6-7 lines on piston sounds ominous. Need a pic to tell.
Simple compression test: Hold pull handle at waist height. Let saw go. Does it go Lub...........Lub..........Lub or Lub..Lub..Lub. 1st one is good, 2nd is bad.