I was cutting this nice dead standing ponderosa pine and by the time I got to bucking my fourth round my saw died. I’ve never had one do this to me before. It kept bogging down slower and slower until it just gradually died. Then the body just started smoking because it was so hot. I was afraid to try and restart it for fear it might catch fire. So I set in in my truck and finished up with by little electric back up saw. I checked the fuel tank and it was still half full. When I came back it was sitting in a big puddle of oil. Any ideas what the issue is? It’s a Stihl ms 291.
I’m not a mechanic. WAG you either toasted some crank bearings or burnt a hole in the piston. Something forced the cases apart to allow the oil reservoir to also leak. Guess it’s also possible the case gasket let loose in the crank area and outside at the same time. Is the plug full of oil?
Remove the muffler and inspect the piston through the exhaust port. I'm guessing it's scored pretty hard. A new top end (or at the least a piston) is in its future if so. Just need to figure out why it did that in the first place before moving forward. Look like this?
I will have to tear into it. Maybe when I have time in a few more days. Thanks for the input. I will post what I find then.
Having replaced it recently likely eliminates it as a cause. I have seen saws that were neglected and the drum worn so thin it breaks apart. Some continued to run it and melt the case surrounding the clutch area until the saw just bogs and quits. The Wood Wolverine has great advice.
Yep, you need to pull the muffler off and then look into the exhaust port. Pull the spark plug and then try and pull it over real slow while looking at the piston moving up and down.
No, its not the brand. I really have no preference or loyalty, almost owned a Stihl a few weeks ago, and wouldnt have felt like I was betraying anyone if I had. Any mechanical device is prone to breakdown. Hope you figure out the issue Timberdog , looks like the start of a good score. How do you loke dispensing gas from that gas can? I just got one like it, but haven't used it on a saw yet....
Sometimes the cylinder can be saved. The issue is finding what caused it to probably leak air to cause the scoring. No chance it was straight gassed?
