FS 85 weed wacker stalling when turned on its side.

[LouinCT]

Hi new to the group. Hello. Any thoughts is much appreciated !!

I have a older Stihl FS 85 weed wacker. I replaced the carb maybe 5 years ago or more with a Stihl carb. It starts, idles, runs and full throttle all fine, when the machine is at normal operating angle, trimmer head is horizontal to the ground. Regular trimming. But once you turn it sideways, muffler side to the ground to do some edging of sidewalks . After a 2 to3 minutes its starts to stall out, unless I turn it and level it out and give it a minute or so it then runs fine. If I turn it with the muffler side to the ground, it starts the hole process over again.

Things I tried.
Gas is good. All my other Stihl products run fine.
Sprayed car cleaner in the carb & in the fuel tank.
The fuel tank is close to full with gas.

Any other thoughts on how, what to fix it ? ?

Thanks

 

[bertsmobile1]

Carb cleaner destroys cube carbs
IF you read the can it specifically says "Throttle body cleaner "
Not working sideways is mechanical fuel delivery problem
So clogger fuel filter, cracked fuel line are what comes to mind first .