WOW! What a thread.
To the OP, Just my humble two cents worth. First off, I have read the entire thread. Secondly, I am not your neighbor, good or bad. Thirdly, you seem to have an attitude problem. People try to help and you go on the attack with disparaging comments, curse words, etc. Now to your problem!
The only common denominator in all of YOUR discussion and what is happening is, in your words, you recently changed SOLVENTS. You will probably find out that the new solvent is deteriorating something in the oil systems. Tubes, vent duckbills, worm gears, etc. 5 different saws. All with the same problem. New SOLVENT. Bingo!!!!!
Like Stihltech, I'm out of here.
OT