FS-550 Max RPM

[Heffalump]

The manual specs max shaft/head speed at 9500RPM. I very much feel like the motor is happier around 10,500.

Question: Does anyone have any better data or personal experience with RPM settings on an FS-550?

 

[DND 9000]

The Gear ratio on the FS 550 is: 1:1.33. That`s why the cutting attachment isn`t turning the same rpms as the engine.

Max engine speed is 12500 rpm. There the electronic speed limiter is activated. I would tune it to around 12000 rpm and see how it is running.

 

[Heffalump]

Good info!!

I stopped in the local Stihl dealer and was told (by the top maintenance tech) that there is no gear reduction anywhere in the unit; direct drive all the way down. That didn't make sense since the head unit was rated to 12.5k and ALL the head tools are max speed around 10k.

Thank you!!

 

[AVB]

Sometime the techs are not that well informed about things. Here's an example what happen to one my customers at John Deere service center.

He want why the low oil pressure was coming on randomly. He was told the engine on F925A ztr did not have oil pump when it clearly had a oil filter and a low oil pressure indicator light. The customer finally let me take a look at it. I look up the engine and it clearly showed an oil pump and pressure sensor. Figuring it was a faulty sensor I replaced it and the customer no longer has the light flashing randomly. He is no allowing JD dealer to service his mower.