Stihl MS 291 having Main Bearing Problems

[drc35ca]

I bought a Stihl MS 291 with 20 inch bar in late fall 2018,crank bearing let go within 1 week and im mixing my oil heavier than was recommended at 1 bottle to 4 liters instead of 5 liters and again my bottom bearing let go sometime in March that i was unaware till i fired it up again in May to clear some wood and noticed it was running lean and would not rev up,now after the dealer telling me it was the carb,getting it back and trying it out still leaned out after 1 minute run ! brought it back,said the seal were bad ,went to pick it up said then the bearing were gone again! Now STIHL waiting and we are july 22nd and I have only burnt 3 to 4 liters of fuel! When it does work it cuts like a hot knife through butter but i am getting fed up with the crank bearing problem. I have been told the race cage is plastic and prone to failure.. Ready to go to another Brand but it seems their all junk?

 

[SOS Ridgerider]

Moved it to the general chainsaw page for you. It’ll get more traffic there.

 

[Thumper88]

You bought it brand new and it’s given these issues? Gather up your documentation and send an email to Stihl headquarters customer service. No saw should have these kinds of issues that fast.

 

[Nutball]

How many ml are in a bottle? You are mixing no more than a ratio of 40:1 correct? I used a 291 at 40:1, and it was on the edge of running lean in cool weather with no way to tune it richer. Maybe poor quality oil coupled with extra hot running from running lean cooked the plastic bearing cage. More oil will make an engine run leaner, but you don't want to use less than 50:1. Pro grade saws are usually where the quality is. Farm/ranch and little homeowner saws are not as good even from high quality brands like Stihl.

You could try a 59cc Echo, and run Echo oil. They have some good quality stuff while being affordable.

 

[lehman live edge slab]

Stihl actually had a bad batch of crank bearings for the 271/291. I bought a saw that the dealer exchanged for a new one because pto bearing let go but it still ran. Pulled the saw down and the bearing came apart in two. Put new bearings and seals in sold it been going about 1 1/2 years so far so good.

 

[drc35ca]

There's a plastic race cage and it keeps coming apart,I had told them last time to get rid of those bearings and go with High end Bearings and Ill pay the difference but I guess no one was listening to my orders so ill have to buy another Manufacturer because a 600$ Saw is not supposed to go to junk after 2 to 5 tanks of fuel and Im mixing a bit heavier than recommended with Stihl Oil, 1 bottle to 4 liters of fuel and it says 5 liters to a bottle

 

[lehman live edge slab]

I haven’t had any issues with the factory bearings. And you’ll be disappointed to know a lot of both husky and Stihl saws have the plastic bearing separators. The crankcase doesn’t get that hot the plastic is probably good to 4-500 degrees and if the plastic cage lets go it doesn’t blow the rest of the saw up. Metal separator fails it can wipe the rest of the saw out as it runs through the saw pounding the cylinder and piston ect.

 

[a. palmer jr.]

Stihl actually had a bad batch of crank bearings for the 271/291. I bought a saw that the dealer exchanged for a new one because pto bearing let go but it still ran. Pulled the saw down and the bearing came apart in two. Put new bearings and seals in sold it been going about 1 1/2 years so far so good.

They certainly did. I've worked on several of them and it usually involves changing at least one main bearing. I don't own one of those but if I did I think I'd run it about 25:1.

 

[lehman live edge slab]

The one I got was only a few weeks old when it failed but after the new bearings it’s been great. The guy runs it 50:1 and runs the heck out of it cutting firewood and quite a few larger maple and oak at his cabin

 

[Nutball]

Plastic is usually only good to 200-400deg. If I remember correctly Stihl oil leaves a saw looking a bit dry inside compared to other oils, and more oil can = leaner and hotter running, especially as lean as saws come from the store these days. 25:1 would make it super lean.

Return it and get you a Husqvarna 550xp mkII or an Echo 590.

 

[Terry Syd]

The stock main bearings on my old 029 were 7-ball and plastic races. A set of 8-ball, metal races came with the Chinese 390 jug I put on it.

I eventually had to go back in to replace the OEM bearings as the crank would wobble when the saw was on the ground. I put the Chinese bearings in and the saw has been fine for two years.

Whatever manufacturer you decide to go with, get the 8-ball bearings. Sometimes OEM is not the best choice.

 

[drc35ca]

I Received My Saw Today,Bearings are now metal raced!

 

[Nutball]

Just some things to keep in mind, I'm not saying you do any of these things wrong:

Make sure you keep the chain sharp and let the saw do the work. Pushing the saw too hard through the wood can run it at a low enough rpm where the clutch can slip a lot, it can slip while the chain still turns, but usually the chain rotation will stall under such conditions. This can overheat the clutch in seconds transferring that heat to the bearings. Keep the rpm up. Also don't let the saw fast idle with the brake on to warm up. Immediately after starting release the brake or the clutch will reach several hundred degrees in a few seconds.

 

[Wilhelm]

I hope Your saw issues have been resolved.

I just looked up local to me Stihl prices, they are too damn proud of their products.
No Stihl for me, I refuse to fund their high strung ambitions.

Good luck with Your 291!

 

[lehman live edge slab]

Bearings and seals were 80-100$

 

[Gord]

Just pulled down a 391 and same thing- junk bearings - some keeper bits mashed to the top of the cylinder but did sme damage to the pison and chrome plating is showing signs of getting thin- going to suggest to him it isn't worh it, don't know why stihl used those bearing for so many years on other saws as well