This is very strange. I made a detailed review of 750SW here and had no problems other than a slight decrease in speed, but still much faster than PA747. Are you running vertical, horizontal, or angled?
Have you lubricated your thrust bearing lately?
What was the last color you ran? Have you extruded black any time recently?
What type of colorant do you use; masterbatch or powder?
Some colorants stain more than others, especially Blue powder-based colorant. Black can take up to 500g to purge it all. I understand you soaked everything in acetone, but with powder colorants (as an example), it needs a little elbow grease to really get it clean without sacrificing virgin pellets. it also sounds like you have two things going on here. Anytime I lose speed, I check the thrust bearing and tweak the SPB as needed. If you have a damaged/under-lubricated thrust bearing, you will drop production speed more and more as time goes. Here's a report I made one year ago http://www.soliforum.com/topic/15622/wh … ugh-today/
Also, as OS3DP mentioned, raise your temps to 192c and go from there.
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