almondgt
Addicted to ArboristSite
There is some confusion about open port and closed port on these saws. It seems to me that a 5000 is the same as a 500, but a 5000+ is different. Then there were apparently late model and early model 5000's and some of them were open port. I'm not sure if anyone ever really figured it out yet. And I have also seen both open and closed port 500's.
Partner 500 ipl shows part number for an open port 44mm piston
All Partner 5000 should be closed port 44mm
All Partner 5000+ should be closed port 44mm to the best of my knowledge