MS 251 Dis-assembly

[sonny580]

Bought this 251 at an auction and its history. sprocket bearing is out and plastic burned but still usable, paint burned off the bar, gas is fresh but smells weird! I never smelled gas like that before so have no idea what they had in it.
Motor turns over but really stiff and from a half azzed comp test looks like around 90 pounds or so. Cant get muffler off, got carb and most everything else off except the flywheel wont come off and the motor is loose but wont come out of the case.
I need to get it completely apart so I can put a new motor back it it. I never took a sthil apart before and probably never take another one apart!! lol! Talk about going around the block just to cross the street!!!LOL
Homelite, Mac,s, and Poulans are a piece of cake to work on!
If you guys can steer me in the right direction on this one, I would be greatfull! Went this far on it and would like to get back to runnin again so I can use it.

 

[HarleyT]

I made a video of me tearing down a new MS271, which is similar.

 

[HarleyT]

Here is part 2.

 

[HarleyT]

Stale gas smells odd and can gunk up a saw tiotally. Also what happens, is that the guy that used it used a gas container that isn't rated for gasoline, and the gas dissolved the plastic, and the plastic cooks down in the saw engine.

 

[sonny580]

Thanks guys! As soon as I get a little time I will tackle it again! Have the flywheel off,--- It fell off while I was trying to get the clutch off,----never did get the clutch off, ---left hand threads,--right??? anyway the flywheel key is sheared off and no pieces in there, so I assume they lined the keyway up and really tightened the nut to hold it on. Looks like I need a flywheel too! ( Poor ole saw!!!)

 

[HarleyT]

Thanks guys! As soon as I get a little time I will tackle it again! Have the flywheel off,--- It fell off while I was trying to get the clutch off,----never did get the clutch off, ---left hand threads,--right??? anyway the flywheel key is sheared off and no pieces in there, so I assume they lined the keyway up and really tightened the nut to hold it on. Looks like I need a flywheel too! ( Poor ole saw!!!)

I am parting one out to put back up on e-bay here soon.

 

[sonny580]

Harley! --- LOVED the videos! --- might have saw the reason I cant get the clutch off ---- I am trying to go the wrong direction! in your vid you said clockwise and I was going the other way! Next round with it I will try the other way.
The last session with it I still cant get the muffler screws loose! These are TIGHT! -- any secrets to getting them out??? Thanks!!

 

[HarleyT]

You really need a drill driver with a good long t27 torx bit. The impact action is the best aspect.