Stihl FS 90 R trimmer Parts Identificaton


Help needed in Stihl FS 90 R Parts Identification

My local Stihl service shop took apart my FS 90 R trimmer to troubleshoot it stalling out. They said the carburetor was bad. I couldn’t afford to have them to the $230 repair, so they gave me back the trimmer and a plastic bag of all the parts they took off. I ordered a new carb and have everything put back together, with the exception of a molded, hard rubber part that is about 16mm wide, 15mm tall, and 8mm deep. It has “slots” at the top and bottom where it seemsĀ the part attached to something. Molded into the “front” of the part is the little Stihl symbol, the numeral “2”, and immediately below the number “4180 A“. I don’t know if the part is associated with the fuel system or electrical system.

Can you give me an idea of what the part is and where it goes as I try to reassemble my trimmer? I’ve looked through the Service Manual and can find no reference to it in text or drawings.

  • Bill Culbertson asked 1 year ago
  • last edited 1 year ago

Yes, this particular Stihl FS 90 R has a 4180 engine in it (as model number shows). Download the free parts list manual in PDF and you should be able to correctly identify the exact part for this trimmer.

Does it look like any part in this diagram? if not just download the full free pdf parts list, you will find it there along with a description and part number.

Stihl FS 90 R Parts list

Stihl FS90R, FS 90 R Schematic diagram parts list


The numbers on the hard rubber part refers to the stihl engine type “STIHL Basismotor 4180” used in the FS 90 R trimmer, could this part just be a model plate for the stihl trimmer.

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