Stihl BG86 CE Tank Vent

[Kevin]

Hi everyone,

If I haven't seen a stihl machine before I change the tank vent as part of the service. About two weeks ago I serviced a BG86 C-E blower and then the owner contacted me and said he was having problems starting it then he said that it had locked up. I immediately thought that it was a fluid lock caused by the pressure in the tank pushing fuel through the carb and into the engine. This proved to be the case with this blower. When I examined the tank vent I noticed that the transparent disc that sits between the foam filter and the tank contents has been replaced by a grey hard, thick cardboard type material. This appears to be the cause of the tank building up pressure. I have looked at another new vent that I have and this is the same. Am I being stupid and is this meant to be removed before installation?

The OEM part number is 0000 350 5800.

Cheers

kevin

[Mick]

I'm not sure about the breather, but the tank will gain pressure as the fuel gasses, it's only designed to let air in not out. It's very common for the blowers to flood with fuel when not in use, normally due to a worn out pump diaphragm.  If removed and held up to the light you can see tiny holes in them.  Might be worth checking.

I did a post on this here, https://thegardenmachineryforum.co.uk/index.php?topic=29.0