Difference between stihl 20-2 and 40-2 autocut heads

[Mitchwyatt00]

G'day all

What is the difference between the Stihl autocut 20-2 and 40-2 heads besides the fact that one is bigger, hence can run thicker line and more of it? I was hoping that it actually could run longer line and therefore cut more with each pass, but this would require the fitting of a different deflector, which I can find no mention of by Stihl.

Is the size of the body the only difference?

 

[Fred482]

My understanding is that the larger number heads hold more of the same size line. I bought a larger one for my FS250 some years ago. I think it is a 30-2. It holds more line than the smaller, original equipment one did. I still have it in the tool box, loaded for a spare, as I cut in remote spots and don't want "down time" if something breaks.

I do notice the larger head makes the line length a bit shorter, therefore the engine rpm goes up. I've modified the guard/line cutter to allow for longer line length. The MS250 has so much power, if you don't load it with a longer line, the engine sounds like it's over-revving, sometimes hitting the rev limiter. I've also carefully adjusted the carb to be just very slightly on the "rich side", to prevent damage. So far, it's a great machine and works well with the larger head.

I also purchased a spare lower head cover, because those wear out in my operation. I cut at a cemetery, lots of jagged tombstones & concrete. If I stay well away from them, the string lasts a lot longer...:msp_biggrin: