Sthil FS-80 Drive shaft

[seagull369]

Darn flex driveshaft broke on my trimmer. Was trying to figure out the part number for it and came up with 4137-711-3202 for the flex and 4137-711-3200 if I go with a solid one. I also came up with 4137-711-3203, but not sure how accurate that one is.

Could anyone comment if any of those might work and what would be a good price?

Many thanks.

 

[DND 9000]

You could go with the complete drive tube assembly of the FS 85 RX. That has a solid drive shaft. Use drive tube assembly 4137 710 7118 together with drive shaft 4137 710 3202. The FS 85, 85 RX drive tube assembly comes with the flexible liner, plug and warning pictogram (USA version) That should work together.

 

[GlynnC]

If switching from flex shaft to solid shaft, make sure it will fit into the clutch drum and gear box. Not familiar with Stihl, but most other brands, the flex shaft is square shaped on the end, solid shafts are splined. A new gear box head is not cheap and changing the clutch drum is somewhat of a pain!!

 

[DND 9000]

FS 80, 85, 85 RX etc use all the same drive shaft end where it is put in the clutch drum and gear head. The clutch drum is also the same on these models.

 

[seagull369]

My apologies for the loooong delay. Turned out both of those part numbers I mentioned were correct. I went with the solid shaft, as it should hold up better and was the same price as the flex (to my amazement the dealer only wanted $15). I installed it the other day but now noticed the trimmer seems to need a new clutch drum (or at least the bearing in there if it's replaceable) as it shakes up by the power head as things get up to speed. It acted similarly before, just not as pronounced. Maybe the flex shaft helped quiet it down, I dunno.

 

[Timbo74]

This is all good info. I had no idea I could replace the flex shaft with a solid one. I have an FS80, and feared putting a blade on it, due to the flex shaft. I will have to go to the dealer and order a 4137-711-3200....correct?

 

[seagull369]

Right, that's it. Keep in mind that's the # for the 'newer' fs80 model (and, I believe, the fs85), not the older one. I attached a pic of what the newer model looks like. The older one didn't have a plastic cover over the motor like that, plus it had an old-style slide carb. When installing, make sure to apply some white lithium grease up and down the shaft before pushing it down in there. The spray on kind is the easiest to get on.

If you don't have it already, you'll need to get a convert kit for the trimmer so you can use blades with it. It includes a splined washer, a reverse thread nut and 'rider plate.' Looks like you can buy them on Amazon for less than $15. If you buy it from your Stihl dealer, they may try to sell you more to go with that, but you don't need it. For the blade, I use 10" carbide tipped blades meant for table saws as the Stihl ones I've used wear out way too fast and aren't cheap. If you go that route, get one with as many teeth as you can find and realize you'll probably need to increase the arbor size to fit the trimmer. One last tip: When you're using the blade, bring the blade up to speed first then swing the trimmer into the brush you're trying to clear. That typically works better than trying to cut in a fashion similar to how you would with a circular saw or chainsaw, esp on thicker stuff.

 

[Timbo74]

Yep, I have the newer model. Thanks for the info.