Chainsaw Repair

There is a small washer that fits on the crankshaft the keeps the oil pump worm gear away from the crankcase seal. I do not see it in your pictures?

After you install the pump, and set the worm gear into place, when you install the clutch drum with the rim sprocket, the drum must be fitted to the worm . . .

There are pieces of the drum that mesh within the plastic worm gear. If you install the clutch drum without working it into the drive mechanism of the worm gear, everything will be in a bind and the clutch will turn all the time.

The big washer goes between the clutch drum and the clutch spider before you screw the spider on. The writing and the wrench flats go towards the outside of the clutch

There is no need to keep puting the bar and chain on to solve this. Reassemble everything to no bar/chain or cover and the drum should spin fairly easily even with the oiler assembled correctly. If it does not spin easily listen or feel as best you can for any rubbing or scraping and reference where you are feeling it and it may lead you to the problem...ie shoes not retreating correctly will be rubbing on the outside of the drum.......missing spacers will be a rubbing felt through the outer face of the drum most likely near the rim sprocket assembly. I am not extremely familiar with the oiler system on this saw but incorrect engagement should be easily determined by this testing as well? Maybe someone could elaborate more as to how this being incorrect would feel...... and a shot in the dark.... how tight is the chain when this is happening?