Ms290 stalls during decelleration.

[StihlHead]

Sounds kind of like an impulse line, but that usually causes them to stall on any throttle activity. Also look at the muffler screen for being clogged up. That will casue the same problem as a clogged air filter. Seems odd though... I have had many saws in the 290 line and never had that kind of problem. I had similar problems with a 250 and a 210. The 250 had a vacuum leak and the 210 had a cracked impulse line. Neither held a tune until they were fixed. Usually when a fuel line goes they fail to start or start and stall out right away.

The impulse line is a hose that runs from the base of the engine to the carb where it drives the fuel pump. Make sure that the carb is seated tightly with the 2 nuts that hold it in place. If the carb gets loose the impulse will fail and/or air will get into the intake. Make sure there are no cracks in the fuel line, the impulse line (looks similar) and that the fuel filter is OK and that the gas line is not kinked. It seems like a starved fuel situation to me. Flywheel/coil timing is hard to move with the way they are mounted. The coil may be failing, but that is rare on a newer saw and it would likely fail all around and more at peak RPMs.

 

[Danno77]

I agree about coil stuff. You do bring up a couple of good things to check that haven't been mentioned. Check that muffler screen and I have heard similar problems with a carb that's come loose.

 

[greenbomb]

Update, Unfortunately my 290 is still stalling upon letting off the trigger. It revs good, but after maintaining high revs, then letting off the trigger, it stalls. I've made multiple adjustments to L H and LA.

You probably have it figure out by now , but i was in the same boat . had the saw since new and over time it kept getting worse . Took the air cleaner cover off and pulled the tank vent hose off , . Its right above the fuel cap , which has no vent because its on the side. Found 2 screws in the line . They were probably loose when the saw was new and vented , but as the line got hard with age and shrunk they no longer vented . i just removed them and the saw runs like new now. I want to thank everybody for their suggestions as it saved me a lot of troubled shooting as i did what everyone said to do twice , Not sure what the factory was thinking . So to cap the problem , The fuel tank did not vent , the mixture leaned out , slight seizure . but rings are loose and good compression