Chainsaw Repair

Long story. . .

New OEM MS250 plastic crankcase! Was a take-off where someone bought a new MS250 and sold the parts.

The pan was eaten up as bad as the plastic crankcase so I decided on a new pan, seals, and a tube of Derko for a long term fix.

The spring tip on the worm where it goes in the notch on the clutch bell was worn in two and the worm threads worn right where the pump gear rides on it was real thin. We're only talking about 1/4" of one thread that does all the work. The pump couldn't have been working?

The new worm is made different and doesn't have the washer on the end of it. You have to buy a separate metal washer to cover the clutch mechanism.

Later 025's and all MS250's have the brake mechanism made different and there's a spring holding pin missing from the later cases inside the chamber that holds the chain brake mechanicals. You have to buy a leaf spring as a replacement that serves to hold the brake handle flag up when the brake is off.

This saw was run with a rusted out muffler and burned up the top cover. The 025 has a replacement top cover - still older but newer than the original one that would have had a riveted on metal "025" name plate. The current top cover has a plastic name plane that just snaps on.

There is a bur inside the right hand muffler retaining nut that keeps the nut from going more than fully on the muffler retaining screw. It will not tighten against the muffler. This caused the muffler gasket to burn up on that side. As a result, the heat shield is all distorted. I'll need a new flanged 5m X .8 nut for that side. As a result of the muffler being loose, the exhaust flange on the cylinder was all pocked up. I dressed it with a 12" flat draw file and it looks pretty good now.

The lower right AV buffer was split but the new crankcase had a new buffer in it.

On the replacement top cover, the front buffer in the original 025 donor saw was either busted or missing and the top cover rubbed on the top buffer holding ring of the original crankcase. This wear point is all intermingled with pine rosin.

The muffler is a right new MS250 muffler that has now been muffler modded.

The new crankcase came with a new fuel line and filter as well as the flippy caps.

I made up a new tank vent with some Tygon from Glenn's and the original grub screws from the original vent. I tested the new vent with the Mity Vac and the vent functions like the workshop manual says it should.

All that from a 025 that looked right nice when it came into the shop?

Anyway, it will look nice once again when I get all the parts here and get the saw together.

It will  look like my other Stihl's of this family.