Stihl KM91R Review

[ayoungtexan]

I purchased a brand new Stihl KM91R with the trimmer, edger, and the cultivator attachments from my local Stihl dealer on the 22nd of April. I have used it extensively, the majority of the runtime being on the string trimmer and edger attachments, as well as a little bit of use on the cultivator. During my 2 weeks of owning the 91 and it's attachments, and also running approximately 20 tanks of 93 octane ethanol-free gasoline, mixed at 32:1 with Echo Red Armor oil (my preferred oil of choice), I have gotten the trimmer attachment guard covered in grass. It has been used hard, from trimming lawns, to cutting tall, thick, and wet grass, and edging overgrown sidewalks and driveways. In this review, I will be discussing the pros, cons, and comparing it to my old Echo PAS-2620.

Pros:
1. The power and sheer torque of the 91 is unreal. It definitely outperforms my old 2620, even when it was muffler modded. Nothing can stop this thing, not cutting 3 foot high grass or tilling rock hard soil. It has plenty of power to run the attachments.
2. It is easier to start than the Echo. The Stihl is usually 1-2 pulls from a cold start every time. The Echo usually took 3-4 pulls.
3. It has very comfortable rubber handles, very similar to the Echo.
4. An automatic stop switch and choke, very similar to the Stihl blowers. My old Echo had a manual choke and stop switch.
5. The 4-mix engine sounds badass at idle and at WOT.
6. It is very good on fuel. I can get around 1.5 hours on a full tank of fuel at varying throttle settings and workloads.

Cons:
1. The Autocut 25-2 trimmer head. This isn't a major con, but I do plan on putting a Speed Feed 400 on this, as I liked this about my Echo.
2. It is slightly heavier than my old Echo, again this isn't a major con..

Overall Rating: 9/10. Put a Speed Feed 400 or 450 trimmer head on this thing and I think you'll have a great trimmer for anything sort of job.

 

[CR888]

Don't get a large speed feed head (450 I think) as it won't work well. It'll fit and bolt on to your trimmer.attachment but it won't perform well as its too big (round), you want the smaller speedfeed, that will allow more line between the line regulating blade and the eyelets on the speedfeed head.

 

[angelo c]

Key to 4 mix motor is staying on top of valve adjustments and knowing how to do it. The "cam" on the decompression system is a weak point as well. When adjusted correctly they are pretty good darn runners and real miserly on fuel. To me they feel slightly heavier but vastly "smoother" to operate for long periods. I've got a little redmax 21?? That sits outside for "spot" weeding, and a 110rx when the yard needs a trimming. Same thing with backpacks.

 

[CR888]

The only thing I don't like about the 4mix and I have a km131 and a km94 is the lack of throttle control, they seem to love running WOT or idle but for doing finesse type work trimming around delicate plants where you only want part throttle they are not the best, same when I'm hedge trimming near a wire fence or whatever & you don't want to run full power they struggle compared to the 2 strokes. I wouldn't buy another one, but they were an interesting clever idea that resulted from EPA regs where for a while the 2T was looking doomed to the history books.