Homeowner with Stihl MS391 looking for help.

[bajafx4]

I bought a Stihl MS391 with a 25" bar a few years ago; I believe my dealer told me that I was buying the first one he'd ever seen. I'm not a pro... I'm just a homeowner with several acres of personal property, but a friend and I do maintain a ~50 acre wooded lot for our township. We only run our saws about 4-5 times a year, but each of these jobs usually lasts us about 5-10 days, so they're fairly large jobs (at least to us). Between the two of us, we have a Stihl 192, 210, 270, and 391. I'd like to perform some upgrades to our largest saw, the 391. Please help out any way you can, and please don't tell me that the 391 is a pig and to sell it or trade it for a 440 or larger. In hindsight, I actually use the 391 more than any other saw and wish I had purchased the 362 pro saw with slightly more power and 1 pound lighter... but it's too late for that.

Question 1 - Chain:
The 391 came with a green link Super 3 RS3 (part 3624). I replaced the OEM safety chain with a few yellow link Micro 3 RM3 (3662). Contrary to what some say about the 391, it actually pulls this chain really well, but it does bog down if I really lean on it. I've read that a full or half skip works well on this saw with this size bar. Can anyone make a recommendation for which chain to try?

Question 2 - Felling Dogs / Clutch Cover:
I'd like to add dual dogs to this saw. My stock clutch cover is plastic. Can someone give advice on how to add a 2nd felling dog? I've found a metal clutch cover with the 2nd dog for a 390, but it doesn't specifically say 391 and I don't know if they're the same. Does anyone know if any of the larger Stilh saw clutch covers will fit on the 391?

Question 3 - Muffler Mod:
Any specific pictures or instructions for this saw? People say they've modded it and that it helped, but I'm just wondering what size hole to drill and where to drill it. I read that another member here (Arrowhead) did a muffler mod that was successful for another fellow member, but there were no pictures or instructions.

Thanks for your help,
Baja

 

[Nate66n1]

View attachment 306959this is my wanna be pro saw. I run a 25" es bar and 25" full comp yellow label chain 3/8 .050. I cant complain about it. The clutch cover I got off a 362 wrap version. The only modification I had to make was oblong the adjuster hole. Bolted up my stock 660 dogs and shes good to go. On the inner dog I had to clearance it torwards the bottom of the case. The muffler mod all I really did was take the spark arrestor out and open up the stock port. Dont forget to pull the limiters while your at it. Hope this helps some

 

[mattthompson]

I did a muffler mod on my 029/039 hybrid saw and I took a punch and punched holes into the center of the cavity and ground the deflector opening a bit wider so it doesn't go straight out the front but kinda like a 45 degree angle perpendicular to straight out the front. Here is a pic of how I opened up the mufflerView attachment 306968

 

[bajafx4]

View attachment 306959this is my wanna be pro saw. I run a 25" es bar and 25" full comp yellow label chain 3/8 .050. I cant complain about it. The clutch cover I got off a 362 wrap version. The only modification I had to make was oblong the adjuster hole. Bolted up my stock 660 dogs and shes good to go. On the inner dog I had to clearance it torwards the bottom of the case. The muffler mod all I really did was take the spark arrestor out and open up the stock port. Dont forget to pull the limiters while your at it. Hope this helps some

Nate - Thanks for the reply. It sounds like you're using the same chain I am. I can't really complain about it either, I just heard this saw pulls a skip better with a 25" bar. Is the clutch cover on a wrap handle 362 different than the standard handle?

 

[Roll Tide]

Nate - Thanks for the reply. It sounds like you're using the same chain I am. I can't really complain about it either, I just heard this saw pulls a skip better with a 25" bar. Is the clutch cover on a wrap handle 362 different than the standard handle?

Yes sir the clutch cover on the wrap version extends down farther.

 

[bajafx4]

Ok, I'm going to stop by my Stihl dealer on my way home today to order the 362R clutch cover. I'm assuming that a Stihl dealer is the only place I can pick one of these up new, correct?

View attachment 307106
Photo shows the difference in the 660/660R and 362/362R clutch cover and dogs for future reference.
It appears that Nate66n1 has the dogs from the 660, but I assume both the standard 660 and 660R will fit with the 362R cover?

 

[Philip Wheelock]

I bought a Stihl MS391 with a 25" bar a few years ago...I'd like to perform some upgrades to ... the 391. Please help out...

Main suggestion is run a 20" bar with a wicked sharp chain and save the 25" bar for bigger stuff. Not sure a metal clutch cover and double dogs will add that much. My stock 440's are happy with 20" bars and I wouldn't want to go longer.

View attachment 307113 View attachment 307114

Nice gig with the town land, BTW.

 

[Brushwacker]

I am not sure if the after market clutch covers are worth the money or not. I've bought a few but haven't used them myself yet. A friend with a tree service took 1 or 2 in the last year and hasn't complained. At least some of what I bought, came with a spike and the bumpers.
I prefer RM yellow label chain. Skip works great in big wood and I find it easier to maintain. I expect in small wood full comp is likely smoother but when going to a 25" bar is because I have mostly big wood. Never the less I use mostly full comp because I shop and usually find it cheaper . I don't pass up full chisel if its cheap enough and I do like full chisel skip.
Muffler mods help significantly on many model saws, but keeping a chain near 100% properly sharpened with a good bar and sprocket is the bigger advantage. I strive to start with a very sharp chain and touch up when needed, but carry extra chains so I can switch if I dull 1 much more then a touch up. I keep an extra bar, 2 or more in my truck when working bigger jobs mostly also.

 

[Nate66n1]

Keeping a sharp chain is definitely the best improvement you could do. My dogs came off of my standard ms 660. Like I said there's a little grinding to do on the inner but not much. I'll take some pics of it when I get out to the shed tonight.

 

[Nate66n1]

View attachment 307164View attachment 307165

 

[rburg]

The rm and the rs chain come in skip version. You may have to see if your dealer can make a loop for you. You can also get the jgx oregon chain from some of the site sponsors that would work on your saw. I use the jgx on a saw with about the same power rating of the 391 and I like the way it cuts plus it is quicker to sharpen than full comp chain.

 

[bajafx4]

Well I think I'll be passing on the 362R clutch cover. I stopped by the Stihl dealer yesterday and they wanted $78 for the cover and I think it was another $25 for the inner and outer 660 dogs. I think my 391 was about $550 when I purchased it, so investing $100 into it pretty much puts me at the cost of a 362 and it will still be a 391. I may sell the 270, put a 20" bar on the 391, and add a 362 or 440/441 to our fleet.

This last job we did had us falling and bucking some pretty large trees, some just over 36" diameter, and the 391 was working on the big stuff if you tried to rush it (which I tend to do... can't help it). It looks like there's some more big stuff in our future too, so a pro saw might be a good addition. The pics below were taken on day 2 of 6 of this job, so all the wood isn't pictured. Overall we generated about 20-25 face cords, mostly old maple, but some elm, hickory, walnut, and dead ash. This may not seem like a large job to some of you guys, but to my partner and I (weekend & after-work warriors) it was pretty big.

View attachment 307220
View attachment 307221
View attachment 307222

I'm still planning on doing the muffler mod to the 391 though.

 

[bajafx4]

Thanks again for all your guys help... it's been very informative.

Also, my dealer told me that the wrap version of the 362, the 362R, has been discontinued. Is this true? It's still on the Stihl website.

 

[Nate66n1]

Ouch, your dealer is definitely more pricier then the one I deal with. Its probably a good idea to get a bigger saw though. You can never go wrong getting a bigger saw. As far as I know the 362r is not discontinued unless your dealer knows more then mine because I was just inquiring about one.

 

[Brushwacker]

Anything your 391 struggles with, the 362 will be little different, a well tuned ms440 with a muffler mod would be a step up, not sure if the 441 is significantly better. If you want to really pick up the pace and not strain saws go for something like an 046 to an ms660, used if you shop u should find something beteen $350 to $600 very decent usable condition.
I would keep the 270, slap a 16" 3/8 bar + chain setup then use it for a beater saw in adverse conditions. Compact to carry, a jiffy that way to sharpen and makes since not to put in high risk or abuse more expensive equipment if u can avoid it. You will not need to replace longer bars and chain as often. U probably will have some delimbing situations it will save some wear and tear on your self also.
I much prefer 3 saws but if money is a problem the 391 might well fetch you 2/3 the cost of something like an ms460 in similar condition.

 

[7sleeper]

I understand that this wasn't what you wanted to read and I know your prefered brand is Stihl, but I would begin starting to think about another (cheaper) brand and upgrading. Often you can buy a pro grade saw from one of the minor players for the price of a semi pro / farmer saw of the major players. Especially with the amount and size of wood you are handling. That in my eyes is definately 70cc territory if you consider the classic 2 stroke or 60 cc territory of the new modern modded AutoTune/MTronic saws.
In your situation I would seriously think about selling the 391 and getting something larger. There is a reason why the typical recomendation is 50 & 70 cc and not 50 & 60 cc. Other brands I would seriously consider would be a dolmar 7900! That will get your wood cutting into a new dimension. But then again it might be a mistake, because you and your partner might start fighting over the saw....
It is always a good idea to contact the guys from here on used equipment (f.e. nmurph). You can usually get excellent used equipment from them.

Muffler modding isn't very difficult. I have also learned it from here.
1. Dismantle your muffler
2. Measure your cylinder muffler outlet hole
3. Open up your muffler exit to the same size and add the spark arrestor again. Should be a more than sufficient safety margin. (Hope that the baffles on the inside aren't to restrictive, if yes, they will also require some opening)
4. Retune the carburator or your saw my fry
5. Go back sawing

Good luck!

7

 

[bajafx4]

Ouch, your dealer is definitely more pricier then the one I deal with. Its probably a good idea to get a bigger saw though. You can never go wrong getting a bigger saw. As far as I know the 362r is not discontinued unless your dealer knows more then mine because I was just inquiring about one.

Nate - They said I was going to need two pieces. The clutch cover itself and then a plastic piece that goes between the clutch cover and the saw body near the rear of the cover? Does this make sense? The parts guy said that this piece on my saw would not line up with the 362R clutch cover and that's why I needed it. They sold them as an assembly for $78 or you could just buy the cover, but I didn't get a price just for that.

 

[bajafx4]

For those interested, I did install a skip tooth chain on the MS391. I got an Oregon 72JGX084G (Oregon's version of Stihl RSF). It does cut a little rougher (slightly more vibration) in smaller wood (under 16" diameter), but the bigger the wood and/or if the entire bar is buried, it cuts a bit faster than the non-skip version. Also, I'm definitely not complaining about the sharpening time!

 

[bajafx4]

View attachment 308018

I've been using my saw to "split" some really large pieces of old maple just to get them to a manageable size to be moved to the splitter. Cutting with the grain really generates some long stringy chips that jam up in my chain catch. Sometimes they jam up bad enough to jam up and bog down the saw. If I added the 2nd dog so I could install a roller catch and removed the stock chain catch, would it alleviate this problem a bit?

 

[rburg]

I am glad to see you tried the skip chain. I think it definitely helps saws the size of the 391 with the 25" bar on it. I currently have one on my 2171 and I definitely like it better when it comes time to sharpen the chain, but it also works well when I am using the saw to noodle some of the bigger pieces. If you hold your saw at an angle to the wood you are noodling, the stringy wood will be much smaller. A wide discharge clutch cover helps also.