MS 261 Troubleshoot

[canopyking]

My 261, about 1 year old, has recently been served for the soon to be describe issue. All the basics were covered, fuel filter, spark plug, air filter, also a few seals on the carburetor and a new gas vent were installed. However, it still never wants to start after the first run one the day, and slowly lowers rpm max speed when in wood bigger than 8-10", all the way to me wondering if it is going to die mid cut. An mtronic reset will bring the rpms back to where they should be, but again, put it in the bigger wood and start dogging at all, and the rpms cut.

I'm thinking it might be a fuel thing, which is where I will start looking next, but just curious if anyone else has experienced this.

This performance is really making me look at Ecchos for the sake of having a gods honest carburetor.

 

[Friedrich]

never had such a problem with my 261‘s but i use premix so you might be right ..

 

[Chris Schultz]

Do you allow the saw to idle a bit before shutting down? I know the m tronics can get weird if shut down right after a high rev cutting scenario.

 

[canopyking]

@Friedrich By a fuel thing I mean a fuel supply. Maybe a pump. (I'm only 80% certain that the fuel filter has been replaced. Guess I could make that 100%). Also my co workers saws are doing the same thing, but we both use different mixes.

@Chris Schultz That is not a normal practice of my. Do you happen to know the why behind them running weird without the idling before shutoff?? I've just noticed with lots of saw owners, they have some voodoo that keeps theirs saws running or running well, or avoiding them running poorly. As of lately, I just need more reasoning.

 

[Chris Schultz]

IDK to be honest. I’ve read/heard about the m tronics “memory”, and them being affected from a rapid shut down after an under load cut….. I wish I could find where I read, because it made pretty good sense on paper. Knock on wood, all my tune able, and m tronic saws run really well.

 

[ATH]

Maybe the saw calibrates to conditions when it's at idle??? Letting it idle may let it "figure out" the ideal mix ratio? Just guessing, not saying that's the case.

Husqvarna dealer told me never let it run out of gas. When you do, the carb makes adjustments based on the lean mixture as it runs dry. That doesn't reset itself when you go to restart until it's running and it figures out the new normal...makes it easy to flood at next start. I'm not saying that to suggest it's the problem here, but just to say knowing what the chip is programed to do may help develop a more scientific practice of the voodoo needed to keep them going!

 

[Birdyman88]

All the basics were covered, fuel filter, spark plug, air filter, also a few seals on the carburetor and a new gas vent were installed.

Did you check the spark arrestor and clean it too. A clogged screen might cause an issue like you're seeing due to the backpressure building up. On a regular carb, it will just run like crap and die on you, and all you have to do is start it back up. Rinse and repeat. On an mtronic, the carb will actually try to compensate and adjust out to an extreme condition and remain there on shutdown, then you can't get it started again without a reset.