Stihl Ms 211 C would not start. Wet sawdust all over the carb.

[John Rainford]

The saw had been running well and when not in use for a period of time I get it running for 5 minutes every couple of weeks. This week it wouldn't start, so I went through some procedures which I learnt from Spudulike and others last year. When I took the air filter off`, the housing seemed a little more dirty than is usual, but nothing dramatic. When I removed the housing to expose the carb, the carb side of the housing and the carb itself were covered in oily sawdust which has to have been there for a long while. So I figured the issue might be sawdust in the carb and/or a fuel line. Cleaned it all up on the outside of the carb and then set to work on the inside with spray carb cleaner. There were some obvious bits of sawdust sitting on the top diaphragm. Sprayed it all through thoroughly and put it back together. Put some fresh fuel in the tank, cranked it up and it turned over first time. So, for a few minutes I was very pleased with myself, but then I got to thinking about how the sawdust had managed to get beyond the air filter housing and cover the carb. The air filter seemed to be seated correctly and the air filter itself wasn't covered in sawdust. Has anyone got any ideas, so that I can stop it happening again.

[adw]

There will always be saw dust on the exterior of the carb, dust behind the air filter has come through the filter itself, or the filter has not been connected properly and it has come vid the sides of the filter, through the filter I would expect dust, around the sides of the filter dust and larger particles of saw dust.

[spudulike]

As ADW said....the flywheel fan pumps up air to around the air filter. There will always be fine sawdust in this air and it will end up around the carb. 

This is just one reason all arb types should have a compressor and air line to clean their chainsaws.

[Dan Maynard]

Are you saying there was sawdust inside the carb though? Other way in I guess is through the fuel, keep the tank clean around the fillers before you open it to refuel, try not to drop dust in while it's open, make sure the fuel filter is good and change it every now and then.

[John Rainford]

Thanks for the replies. I will keep an eye on it to make sure the filter remains seated properly and the fuel tank remains free of sawdust and check the situation after the next lot of logs get cut.

[bmp01]

Make wood chips not saw dust !

 

Huh?

Well, saw dust has a habit of lingering around the saw, getting sucked in the engine by the flywheel (fan), settling on the air filter etc. Wood chips just get flung out the back and are gone.

 

Maybe more usefully....

Check the O ring on the back of the airbox, possibly nic'd or missing, see picture for location. A leak here will get sawdust to the back of the diaphragm and of course into the airbox. Plus you loose the 'compensator' effect - when the filter gets blocked your fuel mixture will get rich.

Cant say I'm overly impressed by seal around the secondary air feed either, bit of a joke really.

 

HTH.

 

 

[Stubby]

5 minutes ago, bmp01 said:

Make wood chips not saw dust !

 

Huh?

Well, saw dust has a habit of lingering around the saw, getting sucked in the engine by the flywheel (fan), settling on the air filter etc. Wood chips just get flung out the back and are gone.

 

Maybe more usefully....

Check the O ring on the back of the airbox, possibly nic'd or missing, see picture for location. A leak here will get sawdust to the back of the diaphragm and of course into the airbox. Plus you loose the 'compensator' effect - when the filter gets blocked your fuel mixture will get rich.

Cant say I'm overly impressed by seal around the secondary air feed either, bit of a joke really.

 

HTH.

 

 

And to high lite  Dust/chips Keep the chain sharp and the rakers down ! 

[bmp01]

1 hour ago, Stubby said:

And to high lite  Dust/chips Keep the chain sharp and the rakers down ! 

Ah yeah, that 😃