Ms 441 problems

[Boomer099]

Just got a ms 441 it's fires up great an idles fine but when at full throttle it seems to skip I am a newbie an no idea what I got my self into any help would great from y'all thanks

 

[Grendel]

Running the saw at wide open throttle, without any load on the motor, should produce a "four-stroke" sound when properly tuned.

What you are describing is probably normal.

 

[Jed]

Agreed, but what Grendle described is called four-stroking, for reasons I don't understand. Not just normal, but essential... I'm pretty sure a saw with a stratified motor (as the 441 has) would blow-up without it.

 

[Grendel]

Yeah, four stroking, that's what I meant.

 

[Jed]

I do the same thing. The thing I can't figure out is what the heck it is. I wanna say that the pressure in the combustion chamber builds to the extent the piston is forced to make a double stroke, on the upward "throw" and then a double stroke on the downward, but I can't picture this.

Man, it's the blind leading the blind around here. Where the heck are you guys at Al and Kevin?

 

[Grendel]

"Two stroke engines rely on effective scavenging in order to operate correctly. This clears out the combustion exhaust gases from the previous cycle and allows refilling with a clean mix of air and fuel. If scavenging falters, the mixture of unburnable exhaust gas with the new mixture may produce an overall charge that fails to ignite correctly. Only when this charge is further diluted, by pumping through a second volume of clean mixture, does it become flammable again. The engine thus begins to 'fire-and-miss' every second cycle (every four strokes), rather than correctly on every cycle."

Scavenged from the net

Seems like without any load on the engine, it kind of bobbles it's exhaust stroke at high RPM. I'd be interested to hear a more experienced explanation too.

 

[Jed]

Dang... Thanks dude.

 

[FireFighterZero]

Probably okay, but I would be carefull not to run a brand new saw at high idle/ no load.

 

[stig]

Word!

 

[Boomer099]

Thanks guys it's not new it does it when there's no bar but where the bar is on it stops weird to me lol sorry for bugging y'all with this newbie question.

 

[stig]

Jeez, don't run a saw full out with no bar and chain on it.

 

[Peter]

Why would you even do that?

It's a bit like running a car with no wheels.....

 

[Bermy]

Shit, don't run a saw with no bar on of, especially wide open!

All tuning and testing should be in full kit, bar, chain and correct tension,