MS250 Clamshell Rebuild

[IrishGuy]

Hey all,
A few months back, I got an MS025 that had been raw gassed. I got it running but it quickly lost power and had minimal compression. I priced the Stihl parts out at well over $250. I turned to EBay and found a someone selling aftermarket parts kits complete with piston,cylinder,bearings,seals and more for around 65 bucks.
When I tore the engine down, I found that the oil seals and bearing had failed and the seals had discolored.
I am about to rebuild today and I will take pics and do a step by step if anyone is interested.

 

[zogger]

Good howto thread with pics is always appreciated. A full kit for 65 bucks is hard to beat, if the components are worth a flip.

I would imagine you would need to clean up the jug some.

 

[Milkman31]

Always interested in how to videos!! And pix!!

 

[watsonr]

opcorn:

 

[nmurph]

Good howto thread with pics is always appreciated. A full kit for 65 bucks is hard to beat, if the components are worth a flip.

I would imagine you would need to clean up the jug some.

 

[pioneerguy600]

Good howto thread with pics is always appreciated. A full kit for 65 bucks is hard to beat, if the components are worth a flip.

I would imagine you would need to clean up the jug some.

Do these long block kits need cleaning up? I have not used one yet.

 

[zogger]

Do these long block kits need cleaning up? I have not used one yet.

Visually inspect, and feel the edges of the ports, etc to make sure they are beveled enough to not catch a ring.

 

[cedarshark]

I just finished a ms250 and bought a meteor piston,new seals and bearings for about $50. I cleaned the cylinder using the method described on the forum using the rotary tool and emery cloth...no acid. It worked very well and took very little time. Heat the new bearings a little with a propane torch and they will drop right on. Be very careful sliding your seal over the crankshaft that has the circlip. The groove will tend to roll the seal lip under and dislodge the spring. Good luck with the rebuild.

 

[IrishGuy]

So. It is finished. I will upload pictures soon. It runs. But I need to adjust the carburetor. I cut with it. It is nice. Time will tell if it holds up but it seems OK.

 

[cedarshark]

You did that pretty quick!

 

[Ifishsum]

Just finished an MS250 myself - my brother somehow roached the piston and just gave it to me to make up for the other the saw work I've done for him. Jug was good, just a few light aluminum deposits and a LOT of carbon. I put a in new Meteor piston kit w/Caber rings, crank seals, carb kit and a new impulse line. Couldn't resist a muffler mod while I had it off either. First clamshell I've torn down, wasn't too bad as the saw was already halfway apart. Great compression, starts and idles perfect - I'm excited to run it now so I offered to cut up some logs for a co-worker this week. I have 5 good running saws now but I never get to do any cutting, living in the city with no fireplace. Someday they'll come in handy I suppose....mostly I just like making broken things work again.

 

[jeff taswelder]

opcorn:opcorn:

 

[cedarshark]

We need pics or it never happened.

 

[watsonr]

Go easy on that propane torch and heating the bearings, you'll kill the bearing cage really easy doing that. Just lube the crank with some 2 stroke oil and use a deep socket to tap the bearing into place, make sure the socket rests on the inner bearing surface and use a 2x4 with a hole drilled to allow the crank to stick through it. A few taps puts the bearing into place without any extra stress to that new bearing. Even putting the crank in the freezer for a few hours helps, bearing almost slides on by hand then.