ts 400 leaking gas

[Lester Gillett]

We have a stihl TS 400 concrete saw that s blowing gas back out of the carbuator>. I remoe the muffle and the piston looks ok. Need some
answer to this, neve had one do that.

 

[Ozhoo]

Eliminate anything that would cause an overly rich condition. Clogged filter, leaking inlet needle, plugged exhaust. After that, you're left with a worn piston. Especially on a concrete saw, the intake skirt gets too thin to close off the intake port.

 

[Lester Gillett]

I have cleaned the muffler and changed the carb. Filter was full of gas so left it off. it still was putting gas out of the carb.
will have to remove the cylinder to see what is going on.

 

[frank_]

sounds like a worn piston skirt eh, those saws eat a lot of dust
i always fit a $30 p + c with a $10 oem top ring

 

[HarleyT]

Yeah, the intake side of the piston is likely in bad shape.

 

[Lester Gillett]

I removed the cylinder and the piston is in good shape. I think its one of the 400 that i put a new cylinder and piston on .
the only thing I could see was at the intake port there is a small place where it looks the piston not sealing.

 

[HarleyT]

pics??

 

[Lester Gillett]

I will add photos later, need to take them off my phone,

 

[Lester Gillett]

Here is the photo I took of the ts400

 

[Lester Gillett]

Could the cylinder gasket be to thick.

 

[cookies]

ring lands and the sealing edges of the rings are chipped, needs piston and rings