Chainsaw Repair

I have the 1991 Stihl 025 back together.

It is a tight, nice looking, chainsaw.

I spun up a new 62 DL Stihl .325" X .063" X 16" RSC chain for it. It has a new Stihl, made in Germany 16" Rollamatic bar.

Admittedly, there is not much from the year 1991 left? The engine cylinder, clutch spider, Starter assembly, top handle, nuts, and screws. It has a flat style air filter but it is not the first style that was part of the filter cover. I didn't put a new clutch cover on it but the one that came on it is probably a newer one for it looks nicer than the ones on my other late 025 or my MS 250. I declare it a Frankensaw for it is an accumulation of parts from many different years.

I had the clamshell engine assembly apart and put another MS250 pan and Stihl seals on the cylinder. Someone had been there before me for there were scratch marks where someone had removed the Dirko before. There were even little pieces of Yamabond, so it may have been apart twice before?

What would you expect of a 1991 firewood saw that was used on occasion for 23 years?

Even though it was mostly made in USA, it is a German design. I don't consider this a beginning repairman's easy saw to repair. I got it as a bunch of parts in a box and thought about reassembly some and did some trial fit togethers while waiting on parts. It almost has to be put together in a precise order. I was pretty confident of myself until I discovered that it was easier to get a new current brake handle for it rather than use the original burned up one that the new pivot parts for the starter side would not work on. To change the brake handle, I had to remove the starter cover, clutch cover, top chain rub strip, brake cover, brake mechanism, Muffler, etc. and pry for all I was worth to get the old handle out. Then put it all back together.

Due to the basic fact that this chainsaw should be re-assembled in a precise order not documented in the Service Manual, I consider it to be the most difficult chainsaw I've ever worked on. I suppose the 029/039 Stihls are little different? I had a mini Mac 10 and a Homelite 150XL for long periods but I never worked on them.

So the first order of reassembly is to mount the oil pump and pick up line. Then the coil must be mounted so you can run the coil high voltage wire through a little trough. Then the switch assembly wires must be laid in this same trough so when you mount the clamshell engine inside the crankcase/tank assembly these wires will be outside the plastic shield that goes over the intake side of the engine. The coil wires are very difficult to get past the shield with it already mounted and you can not get the boot up to the spark plug with the top cover mounted. Then the brake handle/brake mechanism must be mounted. The top cover has to be installed before the top handle for part of the cover circles around the top AV buffer of the top handle. The spark plug is best left for last. The starter assembly can be removed/replaced from a complete saw but it is a really tight fit up under the top cover. It has to be pried and snapped into position.

Something I happened to notice is that the MS250 starter assembly has much more cooling than the 025 starter assembly. The inside starter mechanism is the same.

The difference in the way this 44.3 cc 025 runs and my 45.4 cc MS250 runs is not discernible by ear. Maybe by a stop watch while cutting wood? This 025 and my other one and my MS 250 have .325 X 7 tooth spur sprocket clutch bells.

There's another MS250 engine pan,new seals, a new brake handle, oil pump worm, one new buffer, and Walbro WT-215 carb on it besides the bar and crankcase/tank assembly.

Running the saw, it is a prolific oiler with the new un-modified bar and new pump and pickup and drive parts in the new MS250 crankcase/tank assembly.
 
Though the top cover/rear handle is old, it is not 1991 old. The only scratches on the top cover are underneath in the front by the AV buffer.