Stihl 261CM suddenly stall-prone

   / Stihl 261CM suddenly stall-prone #11  
I dump the gas out of the saw if it's been there a year or so. Kill some weeks or something with it. Just not worth messing with bad gas in a 2 stroke as it can damage the engine with this crummy ethanol gas phase separation problem. New gas mix is better and more consistent operation.
 
   / Stihl 261CM suddenly stall-prone #12  
I’m glad it was an easy fix and you started with cheap stuff. I can’t recall how long ago it was on this forum but someone had a problem with a small engine. I said the same thing I did in this thread, “it’s probably not the spark plug but…..”. This went on for a few days with all sorts of advice. I finally asked if he put a spark plug in. He finally did and you guessed it that fixed it.

I’ve had my fair share of small engines running funny and I think I’ve only once had a spark plug be the problem but it’s also cheap to replace.
 
   / Stihl 261CM suddenly stall-prone #13  
I’m glad it was an easy fix and you started with cheap stuff. I can’t recall how long ago it was on this forum but someone had a problem with a small engine. I said the same thing I did in this thread, “it’s probably not the spark plug but…..”. This went on for a few days with all sorts of advice. I finally asked if he put a spark plug in. He finally did and you guessed it that fixed it.

I’ve had my fair share of small engines running funny and I think I’ve only once had a spark plug be the problem but it’s also cheap to replace.
Rule #1 of small engines, Never trust the spark plug.
 
   / Stihl 261CM suddenly stall-prone #14  
My dad helped a guy tear down lawn mowers that had "died". The guy who showed him the ropes mentioned that he should save all the spark plugs in them. And the reason is that it's the last thing everyone tries before junking the mower. The guy had a giant bucket of brand new spark plugs he'd give away to people who needed a new plug. Recycling at it's finest lol
 
   / Stihl 261CM suddenly stall-prone #15  
I dump the gas out of the saw if it's been there a year or so. Kill some weeks or something with it. Just not worth messing with bad gas in a 2 stroke as it can damage the engine with this crummy ethanol gas phase separation problem. New gas mix is better and more consistent operation.
Yeah, a boatload of issues can be avoided using fresh 91 octane NO ETHANOL fuel in your small engines.
 
   / Stihl 261CM suddenly stall-prone #16  
I had a Husky 550XP that also suffered the bad plug plague. It would start and run fine one minute, minutes later you'd go to start it and nothing. It was frustrating. New plug was all it took.
 
   / Stihl 261CM suddenly stall-prone #17  
I just went through a bout of poor running with my 261C and as stevem5215 said, just dump out the gas and get new fresh fuel. My 500i seems less susceptible to bad fuel, but it might have a newer, hotter spark plug, too.
Mine would start and idle, but then stall as soon you touch the throttle.
Dumped out fuel and went to fresher fuel. Ran perfectly

I think fuel with any ethanol in it goes stale in a matter of weeks now. I mix 5G when I’m on a big sawing/clearing job, but always have in mind to use it all. If it sits more than 3-4 weeks, it’s usually going to give me problems.

Been experimenting with StaBil in my tanks a little bit to see if it’ll help and it really seems to help.
The key is to keep running your saws.
 

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